w  & 


GASEOUS  EXCHANGE  AND  PHYSIOLOGICAL 

REQUIREMENTS  FOR  LEVEL  AND 

GRADE  WALKING 


BY  HENRY  MONMOUTH  SMITH 


PUBLISHED  BY  THE  CARNEGIE  INSTITUTION  OF  WASHINGTON 
WASHINGTON.  APRIL,  1922 


GASEOUS  EXCHANGE  AND  PHYSIOLOGICAL 

REQUIREMENTS  FOR  LEVEL  AND 

GRADE  WALKING 


BY  HENRY  MONMOUTH  SMITH 


PUBLISHED  BY  THE  CARNEGIE  INSTITUTION  OF  WASHINGTON 
WASHINGTON,  APRIL,  1922 


CARNEGIE  INSTITUTION  OF  WASHINGTON 
PUBLICATION  No.  309 


PRESS  OF  GIBSON  BROTHERS 
WASHINGTON 


S7 


PREFACE. 

The  following  report  presents  the  results  of  a  series  of  experiments 
carried  out  in  continuation  of  a  plan  of  study  at  the  Nutrition  Labora- 
tory on  the  energy  expenditure  during  muscular  work,  and  supple- 
ments the  report  of  Benedict  and  Murschhauser:  Energy  Transforma- 
tions during  Horizontal  Walking. 

The  author  is  indebted  to  the  Director,  Dr.  Francis  G.  Benedict, 
for  his  constant  interest  and  criticism  as  the  work  progressed,  and  to 
Miss  A.  N.  Darling  for  her  painstaking  supervision  of  the  editorial 
work  in  preparing  the  material  for  publication.  He  is  also  indebted 
to  Mr.  Karl  H.  Brown  for  his  interest  and  fidelity  in  the  difficult  task 
of  recording  the  pulse-rates  and  to  Mr.  William  H.  Leslie  for  much  of 
the  labor  involved  in  the  calculations,  and  preparation  of  the  tables. 

NUTRITION  LABORATORY  OF  THE 

CARNEGIE  INSTITUTION  OF  WASHINGTON, 

Boston,  Massachusetts,  April  23,  1921. 


CONTENTS. 


PAGE. 

Introduction 1 

Researches  by  other  investigators  on  energy  requirements  for  walking 3 

Horizontal  walking 3 

General  considerations  with  regard  to  previous  researches  on  horizontal 

walking 7 

Grade  walking 8 

General  considerations  with  regard  to  previous  work  on  grade  walking. ...  15 

Plan  of  study 16 

Methods  of  measurement 18 

Universal  respiration  apparatus 20 

Tests  of  the  universal  respiration  apparatus 25 

Treadmill 27 

Measurement  of  the  step-lif  t 30 

Method  of  step-counting 33 

Apparatus  for  determining  the  pulse-rate 33 

Oscillograph 34 

Cambridge  string  galvanometer 34 

Electrodes 35 

Technique  for  securing  records  of  the  pulse-rate 36 

Determination  of  the  body-temperature 36 

Determination  of  the  blood-pressure 37 

Routine  of  experiments 38 

Subjects 41 

Statistics  of  experiments 42 

Discussion  of  results 90 

Basal  metabolism 90 

Experiments  with  subject  standing 94 

Metabolism  during  standing 94 

Carbon-dioxide  elimination 94 

Oxygen  consumption 95 

Respiratory  quotient 95 

Heat-output 96 

General  summary  of  measurements  of  metabolism  during  standing ...  97 

Comparison  of  metabolism  for  lying  and  standing  positions 100 

Physiological  effects  of  standing 101 

Respiration-rate  with  subject  standing 101 

Pulmonary  ventilation  with  subject  standing 103 

Pulse-rate  with  subject  standing 106 

Rectal  body-temperature  with  subject  standing 113 

BJood-pressure  with  subject  standing 115 

Experiments  with  horizontal  walking 116 

Metabolism  of  subjects  while  walking  on  a  level 116 

Total  metabolism  during  horizontal  walking 116 

Increment  in  metabolism  due  to  horizontal  walking 120 

Total  increment  in  heat-production 139 

Increment  in  heat  per  horizontal  kilogrammeter 139 

Effect  of  speed  upon  metabolism  in  horizontal  walking 143 

Effect  of  speed  upon  total  heat-output 145 

Effect  of  speed  upon  total  increase  in  heat-output 146 

Effect  of  speed  upon  increase  in  heat  per  horizontal  kilogrammeter. . .  147 

Experiments  with  subject  "marking  time" 150 

Steps  and  step-lift  during  horizontal  walking 152 

Number  of  steps  in  horizontal  walking 154 

Step-lift  during  horizontal  walking 155 

Possible  causes  for  variation  in  step-lift 155 

Total  step-lif  t  per  minute 156 

Step-lift  per  step 157 

Energy  increment  due  to  work  of  step-lift 157 


Vi  CONTENTS. 

PAGE. 

Discussion  of  results — continued. 

Experiments  with  horizontal  walking — continued. 

Physiological  effects  of  horizontal  walking 160 

Respiration-rate  during  horizontal  walking 160 

Pulmonary  ventilation  during  horizontal  walking 162 

Pulse-rate  during  horizontal  walking 163 

Comparison  of  pulse-rate  during  standing  with  that  during  horizontal 

walking 165 

Relationship  of  oxygen  consumption,  pulse-rate,  and  pulmonary  ven- 
tilation during  horizontal  walking 169 

Body-temperature  during  horizontal  walking 172 

Blood-pressure  during  horizontal  walking 175 

Experiments  with  grade  walking 

Physiology  of  mouth-breathing  appliances 177 

Effect  of  mouthpiece  breathing  upon  metabolism 178 

Effect  of  mouthpiece  breathing  upon  respiration-rate,  pulmonary  ven- 
tilation, and  rate  of  oxygen  consumption 182 

Effect  with  subject  standing 184 

Effect  during  grade  walking 184 

Conclusions  with  regard  to  the  effect  of  long  and  short  preliminary 

mouthpiece  breathing 192 

Metabolism  of  subjects  walking  on  an  incline 193 

Carbon-dioxide  elimination  and  oxygen  consumption   during  grade 

walking 224 

Respiratory  quotient  during  grade  walking 230 

Total  heat-output  during  grade  walking 233 

Increment  in  heat-output  due  to  grade-lift 238 

Total  increment  in  heat  due  to  grade-lift 238 

Increment  in  heat  per  kilogrammeter  of  work  done  in  grade-lift. .  241 

Step-lift  during  grade  walking 243 

Comparison  of  step-lift  in  horizontal  and  grade  walking 246 

Work  of  ascent 248 

Efficiency  in  grade  walking 249 

Efficiency  in  work  due  to  grade-lift '. 249 

Efficiency  in  work  of  ascent 253 

Effect  of  lameness  upon  the  efficiency  of  E.  D.  B 256 

Physiological  effects  of  grade  walking 257 

Respiration-rate  during  grade  walking 257 

Pulmonary  ventilation  during  grade  walking 260 

Pulse-rate  during  grade  walking 262 

Body-temperature  during  grade  walking 268 

Blood-pressure  during  grade  walking 276 

Physiological  changes  in  transition  from  standing  to  grade  walking  and  the 

reverse 277 

Respiratory  changes  in  transition  from  standing  to  grade  walking 278 

Changes  in  respiration-rate 279 

Changes  in  pulmonary  ventilation 284 

Changes  in  rate  of  oxygen  consumption  (unreduced) 284 

Respiratory  changes  in  transition  from  grade  walking  to  standing ....  287 

Changes  in  respiration-rate 288 

Changes  in  pulmonary  ventilation 293 

Changes  in  rate  of  oxygen  consumption  (unreduced) 295 

Conclusions  regarding  respiratory  changes  in  transition  from  grade 

walking  to  standing  and  the  reverse 296 

Pulse-rate  in  transition  from  standing  to  grade  walking 297 

Pulse-rate  in  transition  from  grade  walking  to  standing 303 

After-effects  of  grade  walking 305 

Summary  of  results 309 


ILLUSTRATIONS. 


PAGE. 

FRONTISPIECE.    Subject  and  apparatus  in  readiness  for  experiment. 

Fio.    1.  Treadmill,  with  spirometer  and  various  recording  devices 19 

2.  Double  spirometer 22 

3.  Respiration  counter 24 

4.  Electrical  counter  for  recording  number  of  respirations 24 

5.  Detail  of  valve-operating  device  and  period  counter 28 

6.  Framework  used  in  determining  the  angle  of  ascent , 29 

7.  Step-lift  recorder 30 

8.  Typical  records  of  pulse-rate  as  obtained  with  oscillograph  and  string  gal- 

vanometer         34 

9.  Metabolism  of  E.  D.  B.  in  standing  experiments  without  food 98 

10.  Increments  in  total  heat-output  over  standing  requirement  for  subjects 

walking  on  a  level  at  different  rates  in  meters  per  minute,  with  per- 
centage increase  for  E.  D.  B 146 

11.  Average  energy  cost  per  horizontal  kilogrammeter  of  walking  on  a  level  at 

various  distances  per  minute 148 

12.  Typical  pulse-rate  curves  for  E.  D.  B.  and  W.  K.  during  standing  and  hori- 

zontal-walking experiments 166 

13.  Total  heat-output,  oxygen  consumption,  pulmonary  ventilation,  respira- 

tion-rate, and  pulse-rate  of  E.  D.  B.  and  W.  K.,  referred  to  hori- 
zontal kilogrammeters  for  experiments  with  subjects  walking  on  a 
level  at  different  speeds 170 

14.  Typical  body-temperature  curves  for  E.  D.  B.  during  periods  of  standing 

and  periods  of  walking  on  a  level  at  various  speeds 173 

15.  Reproduction  of  kymograph  records  in  mouthpiece  experiments,  with 

intermittent  renewal  of  oxygen 183 

16.  Total  carbon-dioxide  production  of  T.  H.  H.,  H.  R.  R.,  and  W.  K.,  re- 

ferred to  kilogrammeters  of  work  performed  in  walking  on  different 
grades 225 

17.  Total  carbon-dioxide  production  of  E.  D.  B.  referred  to  kilogrammeters  of 

work  performed  in  walking  on  different  grades 226 

18.  Total  oxygen  consumption  of  T.  H.  H.,  H.  R.  R.,  and  W.  K.  referred  to  kilo- 

grammeters of  work  performed  in  walking  on  different  grades 227 

19.  Total  oxygen  consumption  of  E.  D.  B.  referred  to  kilogrammeters  of  work 

performed  in  walking  on  different  grades 227 

20.  Respiratory  quotients  of  W.  K.  and  E.  D.  B.  referred  to  kilogrammeters 

of  work  performed  in  grade  walking 230 

21.  Total  heat-output  of  W.  K.  referred  to  kilogrammeters  of  work  performed 

in  walking  on  different  grades 234 

22.  Total  heat-output  of  E.  D.  B.  referred  to  kilogrammeters  of  work  performed 

in  walking  on  different  grades 234 

23.  Total  oxygen  consumption  and  heat-production  of  W.  K.  referred  to  kilo- 

grammeters of  work  performed  in  grade  walking 236 

24.  Total  oxygen  consumption  and  heat-production  of  E.  D.  B.  referred  to 

kilogrammeters  of  work  performed  in  grade  walking 237 

25.  Daily  increments  in  heat-production  over  standing  requirement  and  hori- 

zontal component  referred  to  kilogrammeters  of  work  done  in  walking 
experiments  on  different  grades  with  W.  K 239 

26.  Daily  increments  in  heat-production  over  standing  requirement  and  hori- 

zontal component  referred  to  kilogrammeters  of  work  done  in  walking 
experiments  on  different  grades  with  E.  D.  B 239 

27.  Average  increments  in  heat-production  due  to  grade-lift  in  walking  experi- 

ments with  E.  D.  B 240 

vii 


Vlll  ILLUSTRATIONS. 

PAGE. 

FIG.  28.  Pulse-rate,  respiration-rate,  and  pulmonary  ventilation  of  W.  K.  during 

grade  walking,  referred  to  kilogrammeters  of  work 258 

29.  Pulse-rate,  respiration-rate,  and  pulmonary  ventilation  of  E.  D.  B.  during 

grade  walking  referred  to  kilogrammeters  of  work 259 

30.  Typical  pulse  curves  of  E.  D.  B.,  with  subject  standing,  walking  on  a  level, 

and  walking  on  an  incline 265 

31.  Typical  pulse  curves  of  E.  D.  B.,  with  subject  standing  and  walking  on  an 

incline 266 

32.  Typical  pulse  curves  of  E.  D.  B.,  with  subject  standing  and  walking  on  an 

incline 267 

33.  Typical  body-temperature  curves  of  E.  D.  B.,  with  subject  standing  and 

walking  on  an  incline 269 

34.  Typical  body-temperature  curves  of  E.  D.  B.,  with  subject  standing  and 

walking  on  an  incline 271 

35.  Typical  body-temperature  curves  of  E.  D.  B.,  with  subject  standing  and 

walking  on  an  incline 272 

36.  Typical  body-temperature  curves  of  E.  D.  B.,  with  subject  standing  and 

walking  on  an  incline 274 

37.  Contrasting  curves  of  body-temperature  of  E.  D.  B.,  with  subject  standing 

and  walking  on  an  incline 275 

38.  Typical  kymograph  records  of  respiration,  pulmonary  ventilation,  and  rate 

of  oxygen  consumption  in  periods  of  transition  from  standing  to  walk- 
ing and  the  reverse 278 

39.  Duration  of  pulse-cycles  of  E.  D.  B.,  in  transition  from  standing  to  grade 

walking,  as  indicated  by  average  cycle  duration  for  measured  groups 

of  10  pulse-cycles 298 

40.  Duration  of  pulse-cycles  of  E.  D.  B.,  in  grade-walking  experiment  of  Feb- 

ruary 28,  1916,  as  indicated  by  averages  of  2  pulse-cycles,  measured 
individually 300 

41.  Duration  of  pulse-cycles  of  E.  D.  B.,  in  grade-walking  experiment  of  Feb- 

ruary 29,  1916,  as  indicated  by  averages  of  2  pulse-cycles,  measured 
individually 301 

42.  Duration  of  pulse-cycles  of  E.  D.  B.  in  transition  from  grade-walking  to 

standing,  as  indicated  by  average  cycle  duration  for  measured  groups  of 

10  pulse-cycles 304 


GASEOUS  EXCHANGE  AND  PHYSIOLOGICAL  KE- 

QUIEEMENTS  FOE  LEVEL  AND 

GRADE  WALKING 


INTRODUCTION. 

This  investigation  was  undertaken  as  a  part  of  the  larger  plan 
formulated  in  the  Nutrition  Laboratory  some  years  ago  for  the  study 
of  the  energy  requirements  of  the  body  during  muscular  exercise, 
including  a  consideration  of  the  efficiency  with  which  the  human  body 
can  perform  some  of  its  more  common  daily  tasks.  The  results  of 
Atwater  and  Benedict,1  obtained  in  experiments  with  the  respiration 
calorimeter  at  Wesleyan  University,  demonstrated  that  the  energy 
of  the  human  body  could  be  measured  like  that  of  any  machine. 
Accordingly,  when  the  Nutrition  Laboratory  was  established  in  Boston, 
the  plans  for  research  included  a  continuation  of  this  work,  and  a  res- 
piration calorimeter  was  constructed,  which  was  designed  especially 
for  this  type  of  experiment. 

The  results  of  the  studies  of  Zuntz2  and  his  associates  on  the  gaseous 
exchange  of  the  animal  body  demonstrate  that  the  energy  require- 
ments can  be  found  indirectly  by  computation  from  the  oxygen  con- 
sumption and  the  respiratory  quotient  with  an  expenditure  of  much 
less  time  and  effort  than  is  required  for  direct  measurements  by  the 
respiration  calorimeter.  This  has  resulted  in  a  diminishing  use  of 
the  respiration  calorimeter  for  the  energy  measurements  of  the  human 
body,  and  the  data  reported  in  the  following  pages  have  been  obtained 
by  indirect  calorimetry.  However,  it  must  not  be  overlooked  that 
the  respiratioti  calorimeter  first  demonstrated  that  the  law  of  the 
conservation  of  energy  holds  in  the  animal  body  and  that  for  our 
knowledge  of  the  values  used  in  indirect  calorimetry  we  depend  on 
data  obtained  by  direct  calorimetric  measurements. 

The  numerous  comparisons  of  direct  and  indirect  calorimetry 
made  by  Lusk  and  Du  Bois  in  New  York,  with  the  calorimeter  at  the 
Russell  Sage  Institute  of  Pathology,  as  well  as  those  made  with  the 
calorimeters  at  Wesleyan  University  and  later  at  the  Nutrition  Labora- 
tory, have  shown  that  with  severe  muscular  work  the  agreement 
between  the  results  obtained  by  the  direct  and  indirect  methods  is 

'Atwater  and  Benedict,  U.  S.  Dept.  Agr.,  Office  Exp.  Sta.  Bull.  69,  1899;  ibid,  Bull.  109,  1902; 
ibid,  Bull.  136,  1903;  Benedict  and  Milner,  U.  S.  Dept.  Agr.,  Office  Exp.  Sta.  Bull.  175,  1907; 
Benedict  and  Carpenter,  U.  S.  Dept.  Agr.,  Office  Exp.  Sta.  Bull.  208,  1909. 

JZuntz,  Archiv  f.  d.  ges.  Physiol.,  1897,  68,  p.  201.  See,  also,  Zuntz  and  Schumburg,  Physi- 
ologic des  Marsches,  Berlin,  1901,  p.  260. 


2  METABOLISM   DURING   WALKING. 

ideal  for  periods  of  24  hours.  During  rest  experiments  the  agreement 
has  been  shown  to  obtain  for  periods  as  short  as  one  hour.  The  agree- 
ment in  the  short  periods  has  not,  however,  been  thus  far  demonstrated 
under  conditions  of  excessive  muscular  work  with  accompanying 
alterations  in  body-temperature  and  the  possibility  of  over-ventilation 
of  the  lungs,  as  well  as  possibilities  of  special  metabolic  cleavages, 
such  as  lactic  acid. 

In  the  research  here  projected  it  was  definitely  planned  to  conduct 
the  experiments  ultimately  in  a  respiration  chamber  provided  with 
calorimetric  features.  Since  special  stress  was  to  be  laid  upon  the 
measurements  of  ventilation  of  the  lungs,  body-temperature,  heart- 
rate,  and  physiological  factors  other  than  the  metabolism,  it  was 
deemed  wisest  first  to  carry  out  a  series  of  experiments  in  which  the 
subject  walked  upon  a  treadmill  in  the  laboratory  and  was  thus  much 
more  accessible  than  he  would  be  when  walking  upon  a  treadmill  in 
a  respiration  chamber.  It  is  this  series  of  experiments  that  is  reported 
in  this  publication.  The  calorimeter  for  carrying  out  the  work  experi- 
ments planned  has  actually  been  constructed  in  the  Nutrition  Labora- 
tory and  thoroughly  tested  as  to  its  capacity  for  measuring  large 
amounts  of  heat  as  well  as  respiratory  products.  At  the  moment 
of  writing  it  has  not  been  used  for  experiments  with  men  on  the 
treadmill. 

It  is  hoped  that  when  full  information  is  obtained  of  some  of  the 
fundamental  requirements  of  the  human  body  during  periods  of 
muscular  exercise,  scientists  will  be  in  a  better  position  to  consider 
the  question  from  the  standpoint  of  industrial  efficiency,  and  that 
in  the  end  it  may  be  possible  to  state  whether  or  not  a  laborer  should 
be  able  to  perform  a  given  amount  of  work  with  a  greater  efficiency 
than  is  commonly  done,  that  is,  with  less  cost  to  the  body  economy. 
If  such  evidence  is  positive,  the  problem  of  training  the  laborer  and 
determining  in  what  way  the  energy  is  wasted  will  be  the  next  and 
most  obvious  step,  and  the  suggestions  and  criticisms  of  Frederick 
W.  Taylor1  would  have  the  added  support  of  physiological  science. 
Mention  should  also  be  made  here  of  the  very  clever  mechanical 
devices  of  Amar,2  who  has  already  attacked  the  problem  of  efficiency 
in  various  kinds  of  work. 

The  results  of  two  researches3  made  by  this  Laboratory  as  a  part  of 
the  original  plan  have  already  appeared.  The  following  pages  present 
the  results  of  further  study  which  has  been  applied  more  especially 
to  the  work  of  grade  walking.  As  a  necessary  accompaniment  of  a 
study  of  grade  walking,  observations  were  made  with  the  subject 

1  Taylor,  The  principles  of  scientific  management,  New  York,  1911. 
1  Amar,  Le  moteur  humain,  Paris,  1914. 

3Benedict  and  Cathcart,  Carnegie  Inst.  Wash.  Pub.  No.  187,  1913;  Benedict  and  Mursch- 
hauser,  Carnegie  Inst.  Wash.  Pub.  No.  231,  1915. 


RESEARCHES   BY   OTHER   INVESTIGATORS.  3 

walking  on  a  level.  These  served  the  dual  purpose  of  (a)  supplying 
a  suitable  base-line  for  the  proper  study  of  the  special  factors  involved 
in  grade  walking,  and  (6)  supplementing  to  a  not  inconsiderable 
extent  the  present  knowledge  regarding  the  physiology  of  horizontal 
walking.  Additional  data  have  been  collected  on  the  changes  in  the 
pulse-rate,  respiration-rate,  the  pulmonary  ventilation,  and  body- 
temperature  as  affected  by  the  intensity  of  the  work  in  both  horizontal 
and  grade  walking,  and  their  relation  to  the  energy  expended. 

RESEARCHES  BY  OTHER   INVESTIGATORS  ON    ENERGY 
REQUIREMENTS  FOR  WALKING. 

HORIZONTAL  WALKING. 

The  earlier  studies  of  the  energy  metabolism  during  horizontal 
walking  have  been  reviewed  by  Durig1  and  by  Benedict  and  Mursch- 
hauser.2  One  of  the  main  subjects  of  interest  in  this  work  is  the 
determination  of  the  energy  cost  per  horizontal  kilogramme  ter,  i.  e., 
the  energy  cost  of  the  movement  of  1  kilogram  1  meter  in  a  horizontal 
direction.  The  earlier  studies  were  made  under  various  conditions 
of  rest,  food,  altitude,  speed  of  walking,  and  methods  of  computation 
as  regards  the  basal  value.  In  consequence,  the  results  vary  widely, 
Benedict  and  Murschhauser  in  their  summary  table  noting  average 
values  ranging  from  0.308  to  1.169  gram-calories  per  horizontal  kilo- 
grammeter.  Durig  showed  that  when  the  rate  of  walking  was  limited 
to  moderate  speeds  and  the  subject  was  in  the  post-absorptive  condi- 
tion, the  energy  expenditure  was  very  close  to  0.55  gram-calorie  per 
horizontal  kilogrammeter,  but  when  the  speed  exceeded  a  certain 
degree,  given  by  Durig  as  approximately  80  meters  per  minute,  the 
energy  cost  per  horizontal  kilogrammeter  increased.  This  limiting 
speed  Durig'  termed  the  "maximal  economic  velocity."  Reichel,3  in 
Durig's  laboratory,  gave  a  mathematical  formula  to  this  generalization, 
and  Durig  further  states  that  for  each  meter  in  excess  of  the  maximal 
economic  velocity,  the  energy  metabolized  increases  from  1.2  to  1.5 
per  cent  of  the  normal  value. 

In  continuation  of  Durig's  work  and  employing  his  well-established 
methods,  Brezina  and  Kolmer4  conducted  experiments  on  horizontal 
walking  with  and  without  load  at  varying  velocities.  In  these  studies 
the  authors  confirmed  the  results  of  Durig  in  relation  to  the  absence 
of  the  effects  of  speed  below  the  maximal  economic  velocity,  and  add 
that  this  value  is  independent  of  a  load  up  to  21  kg.,  that  is,  a  dead 


rig,  Denkschr.  d.  math.-natur.  Klasse  d.  kaiserl.  Akad.  d.  Wissensch.,  1909,  86,  p.  250. 
2Benedict  and  Murschhauser,  Carnegie  Inst.  Wash.  Pub.  No.  231,  1915. 
3See  Durig,  Denkschr.  d.  math.-natur.  Klasse  d.  kaiserl.  Akad.  d.  Wissensch.,  1909,  86,  pp. 
278  and  279. 
4Brezina  and  Kolmer,  Biochem.  Zeitschr.,  1912,  38,  p.  129. 


4  METABOLISM   DURING   WALKING. 

load  of  21  kg.  can  be  carried  by  the  human  body  as  economically  as 
the  same  amount  of  live  weight.  Above  either  this  load  or  the  maximal 
economic  velocity  the  energy  metabolized  per  horizontal  kilogram- 
meter  increases.  These  authors  further  state  that  if  a  definite  weight 
is  to  be  transported  it  can  be  accomplished  more  economically  by 
increasing  the  load  than  by  increasing  the  velocity.  As  all  these  ob- 
servations were  made  on  but  one  subject  (Brezina),  the  physiologically 
interesting  problem  as  to  the  application  of  these  general  deductions 
to  persons  of  widely  differing  weights  remains  to  be  settled. 
,  Subsequently,  Brezina  and  Reichel1  made  a  study  of  these  data  of 
Brezina  and  Kolmer  in  an  endeavor  to  express  the  relations  between 
the  increase  in  metabolism  and  the  increase  in  load  and  in  velocity. 
They  give  the  results  of  their  treatment  of  the  data  in  the  form  of  two 
generalizations,  (a)  that  for  moderate  speeds  the  cost  of  1  h.  kg.  m. 
is  independent  of  the  speed  and  is  smallest  for  loads  of  approximately 
19  kg.,  and  (6)  that  the  energy  increase  for  loads  above  this  maximum 
weight  of  19  kg.  is  proportional  to  the  square  of  the  load  difference. 

(L— 19)2 

Expressed  in  terms  of  calories,  the  equation  is  C7=0.5H —  ,  in 

10,000 

which  U  equals  calories  per  horizontal  kilogrammeter  and  L  equals 
load  in  kilograms.  Beyond  the  point  of  maximal  economic  velocity, 
the  metabolism  increases  per  horizontal  kilogrammeter  in  geometrical 
ratio  to  the  arithmetical  increase  in  the  speed. 

Benedict  and  Murschhauser2  for  their  two  subjects  found  the  energy 
requirement  per  horizontal  kilogrammeter  to  be  0.507  and  0.493 
gram-calorie,  respectively,  for  speeds  of  approximately  75  meters  per 
minute,  that  the  energy  requirements  increased  with  the  increase  in 
speed,  and  that  running  at  147.5  meters  per  minute  was  more  economi- 
cal than  walking  at  the  same  velocity.  A  measurement  of  the  energy 
required  for  the  elevation  of  the  body  due  to  the  step-movement 
showed  that,  with  a  speed  of  76  meters  per  minute,  one  of  their  sub- 
jects, weighing  73  kg.,  expended  0.65  calorie  in  this  work,  that  is,  23 
per  cent  of  the  increase  in  metabolism  over  the  standing  requirements 
was  due  to  this  work  of  step-elevation. 

Waller,3  in  a  series  of  reports  on  the  physiological  cost  of  various 
forms  of  muscular  work,  included  a  few  experiments  on  horizontal 
walking.  Computations  show  that  his  results  for  speeds  of  approxi- 
mately 100  meters  per  minute  yield  somewhat  over  0.8  gram-calorie 
per  horizontal  kilogrammeter.  Running  at  a  speed  of  approximately 
200  meters  per  minute  gave  a  heat-production  of  about  1.3  gram- 
calories  per  horizontal  kilogrammeter.  The  first  value  is  measurably 

Brezina  and  Reichel,  Biochem.  Zeitschr.,  1914,  63,  p.  170. 

2Benedict  and  Murschhauser,  Carnegie  Inst.  Wash.  Pub.  No.  231,  1915,  pp.  79  and  87. 
3Waller,  Journ.  Physiol.,  1919,  53,  Proc.  Physiol.  Soc.,  p.  xxiv;  see,  also,  Journ.  Physiol.,  1919, 
52,  Proc.  Physiol.  Soc.,  p.  Ixxii. 


RESEARCHES   BY   OTHER   INVESTIGATORS.  5 

higher  than  that  usually  found,  and  may  in  part  be  explained  by  the 
fact  that,  as  Waller  himself  states,  his  method  determines  only  the 
carbon-dioxide  production,  a  respiratory  quotient  is  assumed,  and 
there  is  an  acknowledged  error  of  ±5  per  cent.  In  general,  his  values 
run  somewhat  higher  than  those  commonly  accepted  as  a  result  of 
other  walking  experiments. 

Benedict,  Miles,  Roth,  and  Smith,1  in  the  report  of  a  study  on  the 
effects  of  restricted  diet,  include  the  measurement  of  the  gaseous 
exchange  during  level  walking  on  a  treadmill  of  a  group  of  12  young 
men  in  normal  condition  and  of  the  same  group  after  20  days  of  re- 
stricted diet.  They  likewise  report  the  gaseous  exchange  during  walking 
of  a  group  of  1 1  men  after  they  had  been  on  a  restricted  diet  for  a  period 
of  120  days.  A  special  closed-chamber  method  was  used,  and  the 
carbon  dioxide  produced  and  the  oxygen  consumed  were  determined 
by  analysis  of  the  chamber  air.  They  found  the  average  cost  per 
horizontal  kilogrammeter  for  the  normal  men  to  be  0.597  gram-calorie, 
and  for  the  same  group  after  20  days  of  restricted  diet  0.562  gram- 
calorie.  For  the  group  with  a  restricted  diet  for  120  days  the  cost 
per  horizontal  kilogrammeter  was  0.522  gram-calorie,  thus  indicating 
a  somewhat  greater  efficiency  per  unit  of  work  for  the  men  who  were 
on  a  restricted  diet  and  much  below  then*  usual  body-weight.  These 
figures,  the  authors  state,  were  for  brief  periods  of  moderate  speed 
(70  meters  per  minute)  and  do  not  apply  to  conditions  in  which  con- 
tinued exercise  and  stamina  might  be  prime  requisites. 

Cathcart  and  Orr,2  using  the  Douglas  bag  method,  made  a  series 
of  studies  on  the  energy  requirements  for  the  various  forms  of  exercise 
required  of  British  recruits.  Inasmuch  as  the  experiments  were 
carried  out  under  various  conditions  of  weather  and  terrain,  the 
authors  distinctly  state  that  all  they  could  expect  to  obtain  was  an 
average  of  the  energy  expended  in  performing  any  given  type  of  drill. 
Among  the  many  forms  of  exercise  reported  in  their  publication  was 
included  that  of  marching  with  light  (15.3  kg.),  medium  (20.5  kg.), 
and  heavy  (25  kg.)  loads.  The  speed  was  91.4  meters  per  minute 
on  a  comparatively  level  and  smooth  stretch  of  road.  For  these  con- 
ditions they  found  the  cost  per  horizontal  kilogrammeter  to  be  0.543, 
0.638,  and  0.672  gram-calorie  for  the  several  loads.  In  addition  to 
these  field  tests,  a  series  was  also  made  on  one  of  the  authors  wherein 
the  details  are  more  nearly  those  of  the  laboratory  research  in  which 
the  effects  of  diet  and  the  effects  of  velocity  and  load  were  studied. 
Under  these  conditions  they  found  an  increased  cost  per  horizontal 
kilogrammeter  with  increase  in  speed  and  load  from  approximately 
0.52  gram-calorie  for  a  speed  of  57  meters  per  minute  to  0.85  gram- 
Benedict,  Miles,  Roth,  and  Smith,  Carnegie  Inst.  Wash.  Pub.  No.  280,  1919,  p.  546. 
2Cathcart  and  Orr,  The  energy  expenditure  of  the  infantry  recruit  in  training.  H.  M.  Stationery 
Office,  London,  1919. 


6  METABOLISM   DURING   WALKING. 

calorie  at  a  speed  of  183  meters  per  minute  with  a  load  of  11  kg.,  and 
from  0.48  to  0.72  gram-calorie  with  a  load  of  26  kg.  The  last  value  was, 
however,  for  a  speed  of  110  meters  per  minute.  They  also  found  the 
average  cost  per  horizontal  kilogrammeter  for  three  subjects  walking 
with  a  9  kg.  load  at  speeds  of  55,  82,  and  110  meters  per  minute  to  be 
0.48,  0.51,  and  0.65  gram-calorie. 

Liljestrand  and  Stenstrom1  report  a  series  of  respiration  experiments 
with  the  subjects  either  walking  or  running.  These  authors  used  the 
Douglas  bag,  with  the  men  in  the  post-absorptive  condition.  The 
walking  was  done  on  a  level  track  of  oval  form  in  the  vStadium  a: 
Stockholm.  The  distances  walked  were  100  meters,  with  a  preliminary 
period  of  1  minute  or  longer.  Measurements  for  both  the  sitting  and 
standing  positions  were  also  made.  The  investigators  report  their 
values  as  oxygen  consumed  per  horizontal  kilogrammeter.  After 
deducting  a  resting  value  for  sitting,  they  assumed  a  respiratory  quo- 
tient and  calculated  for  the  subject  N.  S.  (body-weight  80  kg.)  an 
average  cost  per  horizontal  kilogrammeter  of  0.517  gram-calorie  for 
walking  at  a  speed  of  50  to  75  meters  a  minute.  For  a  speed  of  75  to 
100  meters  per  minute  the  cost  was  0.613  gram-calorie,  and  above  100 
meters  per  minute  it  was  0.830  gram-calorie.  For  the  subject  G.  L. 
(body-weight,  60  kg.)  the  energy  cost  at  similar  speeds  was  0.491, 
0.574,  and  0.710  gram-calorie,  respectively. 

In  their  experiments  with  the  subject  running  these  authors  found 
that  the  cost  per  horizontal  kilogrammeter  fell  with  the  increase  in 
speed.  For  the  subject  N.  S.,  with  a  speed  of  from  144  to  175  meters 
per  minute,  the  heat  expenditure  was  1.004  gram-calories  per  hori- 
zontal kilogrammeter.  This  fell  to  0.796  gram-calorie  for  a  speed 
between  225  and  250  meters  per  minute.  Similar  results  were 
found  with  the  subjects  G.  L.  and  E.  S. 

Cathcart,  Lothian,  and  Greenwood2  have  considered  the  energy 
expended  in  relation  to  the  velocity  of  walking  and  take  exceptions 
to  the  generalization  of  Brezina  and  Reichel  that  the  cost  of  movement 
remained  constant  up  to  a  velocity  of  80  meters  per  minute  and  there- 
after increased  geometrically.  They  contend  that  as  a  general  physio- 
logical law  it  involves  a  discontinuity  at  a  fixed  point  between  the 
speed  and  the  energy  expenditure,  and  other  evidence  points  to 
uneconomical  work  at  low  speeds.  Furthermore,  as  an  interpolation 
formula,  they  consider  the  data  upon  which  it  is  based  are  insufficient, 
for  although  they  cover  a  wide  range  of  speed  and  load,  they  relate  to 
but  one  subject.  These  authors,  using  the  data  of  Brezina  and  Reichel, 
show  that  the  relation  between  the  energy  cost  per  unit  of  time  and 
speed  may  be  represented  with  equally  good  approximations  to  the 

'Liljestrand  and  Stenstrom,  Skand.  Archiv  f.  Physiol.,  1920,  39,  p.  167. 
*Cathcart,  Lothian,  and  Greenwood,  Journ.  Roy.  Army  Med.  Corps,  April,  1920. 


RESEARCHES   BY   OTHER   INVESTIGATORS.  7 

observed  values  by  a  formula  differing  from  that  of  Brezina  and 
Reichel.  They  conclude  that  neither  their  own  formula  nor  that  of 
Brezina  and  Reichel  expresses  a  physiological  law  and  that  they  are 
useful  solely  as  interpolation  formulae.  They  also  find  that  by  applying 
their  equation  to  some  150  experiments  made  at  speeds  of  55,  82,  and 
110  meters  per  minute,  the  optimum  rate  of  walking  was  approximately 
82  meters  per  minute,  a  value  close  to  that  found  by  Durig. 

GENERAL  CONSIDERATIONS  WITH  REGARD  TO  PREVIOUS  RESEARCHES  ON 

HORIZONTAL  WALKING. 

From  the  large  mass  of  evidence  obtained  in  European  and  American 
laboratories  on  the  metabolism  during  horizontal  walking,  it  can  be 
seen  that  no  little  portion  of  it  has  been  accumulated  with  the  primary 
object  of  the  transportation  of  loads.  This  has  in  part  been  neces- 
sitated by  the  technique  employed  in  the  Zuntz  school  of  carrying 
on  the  back  a  rather  cumbersome  and  weighty  meter  with  its  attach- 
ments, and  in  part  by  the  fact  that  interest  has  been  stimulated  by 
Alpine  touring.  Certain  fundamental  experiments  have  been  made  in 
laboratories  by  means  of  treadmills.  When  a  pack  was  not  trans- 
ported the  results  of  these  earlier  experiments  are  perfectly  comparable 
with  those  with  free  walking.  They  are,  however,  even  at  best,  too 
few,  and  accumulation  of  further  evidence  is  entirely  justified. 

Practically  all  of  the  results  point  towards  the  excellence  of  the 
work  carried  out  under  the  supervision  of  Durig.  Inherently,  per- 
haps, no  further  investigation  on  horizontal  walking  per  se  is  justifiable 
with  the  great  number  of  other  problems  on  walking  which  await 
solution.  Durig's  main  problem  was  the  study  of  the  metabolism 
for  the  work  of  ascent,  but  unfortunately  nearly  all  of  his  work  included 
not  only  the  transportation  of  a  load  but  the  use  of  a  cumbersome, 
unweildy  gas-meter  carried  on  the  back.  That  these  conditions  do 
not  call  into  play  a  much  larger  degree  of  muscular  coordination  than 
would  ordinarily  be  required  in  free  walking  is  difficult  to  believe. 
On  the  other  hand,  it  is  clear  that  Durig's  values  for  the  energy  required 
to  transport  1  kg.  a  horizontal  meter  are  closely  in  accord  with  the 
results  of  practically  all  the  work  done  by  other  methods,  although,  as 
a  rule,  they  run  slightly  higher,  which  would  be  expected  from  the 
nature  of  the  technique. 

Two  important  points  must  be  considered:  First,  that  for  all  investi- 
gations on  grade  walking,  clearly  established  base-lines  are  necessary. 
These  can  best  be  obtained  by  actual  test,  i.  e.,  by  having  the  subject 
walk  on  a  horizontal  plane  under  exactly  the  same  conditions  as  he  sub- 
sequently walks  on  a  grade.  This  particular  factor  influences  in  large 
part  the  accumulation  of  the  material  on  horizontal  walking  to  be 
given  in  the  present  report. 

Secondly,  evidence  has  been  forthcoming,  although  unfortunately 


8  METABOLISM   DURING   WALKING. 

as  yet  not  accompanied  by  clearly  defined  experimental  proof,  that 
walking  in  free,  open  air  has  a  measurably  different  physiological 
effect  from  that  of. walking  on  a  treadmill  in  a  more  or  less  closed 
laboratory.  In  any  event,  this  effect  must  be  relatively  small  in 
degree  as  compared  to  the  effect  of  grade  walking.  Consequently,  all 
contributions  to  technique  or  to  the  physiology  of  horizontal  walking 
that  will  make  the  establishment  of  the  normal  base-line  more  definite 
are  to  be  welcomed,  for  the  problem  of  the  difference  in  effect  of  walking 
in  the  open  air  as  compared  to  walking  on  a  treadmill  in  a  well-venti- 
lated room  can  only  be  solved  by  the  use  of  impeccable  technique. 

GRADE  WALKING. 

The  majority  of  the  studies  which  involve  grade  walking  have  been 
made  in  connection  with  studies  of  the  effects  of  high  altitudes  upon 
the  physiological  actions  of  the  human  organism.  The  conditions  of 
high  altitudes,  mountain  paths,  and,  in  many  cases,  a  previous  diet, 
must  be  taken  into  consideration  in  examining  the  results.  In  prepara- 
tion for  these  mountain  expeditions,  nearly  all  the  researches  included 
a  series  of  treadmill  experiments  which  alone  are  really  comparable 
with  our  results.  Most  of  the  results  in  these  experiments  were 
obtained  by  the  Zuntz  method.  With  this  method  the  subject 
breathes  through  suitable  valves,  the  volume  of  air  is  measured,  and 
its  composition  determined  by  analysis  of  carefully  drawn  samples. 
From  the  known  heat  value  of  a  cubic  centimeter  of  oxygen  or  carbon 
dioxide  for  the  respiratory  quotient  found,  the  energy  expended  per 
unit  of  tune  is  then  calculated. 

The  basis  for  comparison  was  the  carbon-dioxide  production,  the 
oxygen  consumption,  or  the  heat  expended  per  kilogrammeter  of  work 
done  by  the  subject  in  lifting  his  body-weight,  plus  any  loads  he  carried 
in  the  form  of  equipment,  such  as  gas-meter,  etc.,  to  the  elevation 
attained  by  the  grade,  or  briefly,  the  work  of  the  "grade-lift."  The 
question  of  the  proper  base-line  has  been  variously  treated.  The 
resting  or  maintenance  metabolism  in  either  the  lying  or  the  standing 
position  has  been  universally  deducted  from  the  total  gaseous  exchange 
measured,  but  the  allowance  for  the  so-called  "horizontal  component" 
has  been  variously  regarded.  It  is  more  generally  estimated  as 
equivalent  to  an  equal  linear  distance  found  from  horizontal-walking 
experiments.  In  other  cases,  no  allowance  has  been  made  for  this 
factor,  but  the  energy  expended  per  meter  of  distance  walked  and 
kilogrammeter  of  lift  is  reported. 

In  1891,  Katzenstein1  made  some  measurements  of  the  gaseous 
metabolism  during  grade  walking  in  the  laboratory  of  Zuntz  in  Barlin, 
employing  a  treadmill  and  the  Zuntz  method  of  measuring  the  gaseous 

Katzenstein,  Arch.  f.  d.  ges.  Physiol.,  1891,  49,  p.  330. 


RESEARCHES   BY   OTHER   INVESTIGATORS.  9 

exchange.  Four  subjects  were  used  and  the  basal  metabolism  and  the 
metabolism  during  horizontal  walking  were  determined.  The  grade 
of  the  treadmill  was  of  moderate  pitch,  varying  from  approximately 
10  to  13  per  cent.  As  computed  from  the  respiratory  quotients,  the 
heat-output  was  5.69  to  7.33  calories  per  kilogrammeter,  with  efficien- 
cies of  31.9  to  41.1  per  cent.  The  great  variations  in  the  results  of 
Katzenstein  are  in  no  small  part  due  to  the  wide  differences  in  his 
estimations  of  the  oxygen  consumption  per  horizontal  kilogrammeter, 
which  ranged  from  0.0858  c.  c.  for  his  subject  Zimm  to  0.1682  c.  c.  for 
his  subject  Krzywy,  and  also  to  the  fact  that  the  relatively  low  grade 
of  the  treadmill  did  not  produce  a  large  amount  of  work. 

In  the  same  year  Gruber1  made  a  study  of  the  effect  of  training  in 
the  ascent  of  approximately  80  meters  to  the  Minister  tower  outside 
of  Berne.  The  experiments  were  made  after  a  midday  meal,  and  the 
carbon-dioxide  production  alone  was  determined  by  a  gravimetric 
method.  The  results  are  primarily  of  interest  as  implying  increased 
efficiency  following  training. 

Schumburg  and  Zuntz,2  in  a  study  of  the  effects  of  high  altitudes, 
report  a  series  of  experiments  with  Zuntz  walking  on  a  treadmill  in 
Berlin  at  a  grade  of  31  per  cent  and  a  speed  of  24  meters  per  minute, 
in  which  the  average  oxygen  consumption  per  kilogrammeter  of  work 
done  was  1.77  c.  c.,  or  an  efficiency  of  27  per  cent.  With  Schumburg 
as  the  subject,  the  oxygen  consumption  was  1.73  c.  c.,  with  an  efficiency 
of  28  per  cent.  Later,  these  two  men,  when  walking  up  a  grade  of  31 
per  cent  on  Monte  Rosa,  found  their  efficiencies  to  be  20.9  and  23.2 
per  cent. 

A.  and  J.  Loewy  and  L.  Zuntz,3  preliminary  to  their  expedition  to 
Monte  Rosa,  made  a  series  of  measurements  on  a  treadmill  in  Berlin 
at  grades  of  about  23.0,  30.5,  and  36.6  per  cent.  The  energy  produc- 
tion per  kilogrammeter  of  grade  work,  after  the  resting  value  and  the 
value  for  the  horizontal  component  had  been  deducted,  varied  from 
6.74  to  8.07  calories  per  kilogrammeter  for  A.  L.,  6.53  to  7.30  calories 
for  J.  L.,  and  6.41  to  7.32  calories  for  L.  Z.,  with  efficiencies  from  29 
to  36.5  per  cent.  The  lowest  efficiency  was  found  with  A.  L.  and 
the  highest  with  L.  Z. 

In  the  expedition  on  Monte  Rosa  made  by  these  investigators,  in 
walking  up  grades  of  26  to  33  per  cent  at  Col  d'Olen  with  an  elevation 
of  2,840  meters,  and  at  Capanna  Gnifetti,  with  an  elevation  of  3,620 
meters,  the  metabolism  per  kilogrammeter  of  work  due  to  the  grade 
walking  was  as  follows:  For  A.  L.,  8.13  and  9.11  calories  per  kilograms 
meter;  for  J.  L.,  8.23  and  8.99  calories;  for  L.  Z.,  8.77  and  8.41  calories. 
The  efficiencies  were:  For  A.  L.,  28.8  per  cent  at  Col  d'Olen,  and  25.7 

Gruber,  Zeitschr.  f.  Biol.,  1891,  28,  p.  466. 

2Schumburg  and  Zuntz,  Arch.  f.  d.  ges.  Physiol.,  1896,  63,  p.  461. 

3A.  and  J.  Loewy  and  L.  Zuntz,  Arch.  f.  d.  ges.  Physiol.,  1897,  66,  p.  477. 


10  METABOLISM   DURING   WALKING. 

per  cent  at  Capanna  Gnifetti;  for  J.  L.,  28.4,  and  26.0  per  cent;  and. 
for  L.  Z.,  26.7  and  27.8  per  cent,  respectively. 

Biirgi,1  in  a  study  on  the  effects  of  training,  made  ascents  of  25  per 
cent  grade  at  Brienz  (734  meters)  and  the  Rothqrn  (2,184  meters); 
also  on  the  Gornergrat,  where  the  grade  was  19.3  per  cent  and  the  height 
2,987  meters.  The  carbon  dioxide  only  was  determined  in  these 
experiments. 

From  Biirgi's  results,  Durig2  has  computed  the  energy  required  per 
kilogrammeter  of  grade  work,  using  an  assumed  respiratory  quotient 
of  0.80,  and  found  it  to  be  8.6  to  9.8  calories  at  Brienz,  10.2  to  12.3 
calories  on  the  Rothorn,  and  9.3  calories  on  the  Gornergrat.  After 
training  the  expenditures  were  lower. 

Frentzel  and  Reach,3  in  their  study  on  the  source  of  muscular  power 
reported  some  experiments  in  which  the  subject  walked  on  the  tread- 
mill with  a  grade  of  23  per  cent.  These  experiments,  however,  were 
not  made  with  the  man  in  the  post-absorptive  condition,  but  after  a 
special  diet  of  carbohydrates,  proteins,  or  fats.  From  the  data  for  the 
gaseous  exchange  the  computed  efficiencies  are  36.4  for  F.  and  35  per 
cent  for  R. 

Zuntz  and  Schumburg,4  in  their  comprehensive  study  of  marching, 
included  a  few  experiments  on  grade  walking.  These,  however,  were 
made  with  a  grade  of  only  6.5  per  cent.  We  have  computed  an  effi- 
ciency from  their  data  of  31.2  per  cent. 

Durig  and  Zuntz5  give  the  energy  expended  by  themselves  when 
walking  on  the  glacier  of  Monte  Rosa  as  14.65  and  9.76  calories  per 
kilogrammeter  of  work.  The  low  efficiencies  are  obviously  attribut- 
able to  the  poor  footing. 

Durig,6  in  1906,  made  some  grade  studies  upon  himself  1|  to  2 
hours  after  a  light  breakfast,  when  walking  with  a  load  of  18  kg.  on 
the  Bilkengrat  at  grades  of  25  to  27  per  cent.  In  all,  33  experiments 
were  reported,  showing  an  efficiency  of  25.6  to  29.8  per  cent.  The 
average  expenditure  was  7.9  calories  and  the  average  efficiency  29.S 
per  cent.  Durig  found  that  the  efficiency  increased  with  practice^ 
He  also  found  a  greater  metabolism  in  the  first  periods  of  the  day, 
indicating  need  of  practice  for  each  day,  that  the  path  conditions  had 
little  effect,  and  that  the  respiratory  quotient  had  a  tendency  to  fall. 

In  1901,  Zuntz  and  his  colleagues,  A.  Loewy,  M  tiller,  and  Caspari,7 
spent  the  summer  upon  Monte  Rosa,  where  elaborate  studies  were 

'Biirgi,  Arch.  f.  Anat.  u.  Physiol.,  Physiol.  Abth.,  1900,  p.  509. 

lDurig,  Denkschr.  d.  math.-natur.  Klasse  d.  kaiserl.  Akad.  d.  Wissensch.,  1909,  86,  p.  300. 
'Frentzel  and  Reach,  Arch.  f.  d.  ges.  Physiol.,  1901,  83,  p.  477. 
4Zuntz  and  Schumburg,  Physiologic  des  Marsches,  Berlin,  1901. 

"Durig  and  Zuntz,  Travauz  de  1'annee  1903,  Laboratoire  scientifique  international  du  Mont 
Rosa,  Turin,  1904,  p.  65;  also  Arch.  Anat.  u.  Physiol.,  Physiol.  Abth.,  1904,  Suppbd.,  p.  417. 
*Durig,  Arch.  f.  d.  ges.  Physiol.,  1906,  113,  p.  213. 
7Zuntz,  Loewy,  Miiller,  and  Caspari,  Hohenklima  u.  Bergwanderungen,  Berlin,  1906. 


RESEARCHES    BY    OTHER   INVESTIGATORS. 


11 


carried  out  for  which  preparations  had  been  made  during  the  previous 
winter.  The  report  includes  the  gaseous  exchange  of  the  four  authors 
and  two  others  during  grade  walking  in  treadmill  experiments  in 
Berlin,  and  also  on  the  railroad  up  the  Rothorn,  at  Brienz,  on  Col 
d'Olen,  and  for  a  few  experiments  at  the  Gnifetti-Hiitte  on  Monte 
Rosa.  Table  1  gives  the  computed  percentages  of  efficiency  for  walk- 
ing on  the  different  grades  in  these  experiments. 

TABLE  1. — Percentage  of  efficiency  in  grade-walking  experiments  made  by  Zuntz  and  Durig, 

arid  their  colleagues. 


Subject. 

Treadmill, 
Berfin, 
12.7  p.  ct. 

Brienz 
(500  meters), 
25  p.  ct. 

Rothorn 
(2,  100  meters), 
25  p.  ct. 

Col  d'Olen 
(2,900  meters), 
45  p.  ct. 

Monte  Ross 
(3,700  meters), 
22  p.  ct.  (ca.). 

Zuntz     and     col- 
leagues : 
Waldenburg  .  . 
Kolmer  .  .    . 

32.4 
U6.5 
33.1 
/38.6\ 
\l2Q.3f 
43.3 
42.6 

29.8 
42.7 
33.8 

31.8 

32.7 
38.0 

32.1 
41.9 
32.1 

29.5 

32.5 
33.6 

27.0 

17.7 
19.8 

Caspar!  

Muller  

37.6 

Loewy  

Zunta 

122.6 

Subject. 

Treadmill, 
Vienna, 
21.6  p.  ct. 

Neuwaldegg 
(summer), 
16.4  p.  ct. 

Neuwaldegg 
(winter)  ,' 
16.4  p.  ct. 

Monte  Rosa, 
15.5  p.  ct. 

Durig     and     col- 
leagues: 
Durig  

f34.9\ 
V34.1/ 

31.1 

30.3 
31.7 
30.1 

24.0 

20.9 
15.2 
21.8 

21.2 

18.5 
21.5 
19.8 

Kolmer  

Rainer  

Reichel  

Durig,2  in  the  report  of  his  expedition  to  Monte  Rosa,  presents  a 
critical  view  of  the  preceding  studies  and  also  gives  the  results  obtained 
by  himself  and  his  companions,  Kolmer,  Rainer,  and  Reichel,  at 
Vienna  and  on  Monte  Rosa.  The  computed  percentages  of  efficiency 
for  these  experiments  are  also  included  in  table  1.  Like  the  preceding 
work  of  Durig,  these  studies  were  carried  out  by  the  Zuntz  method, 
with  all  of  the  Durig  refinements.  Durig  notes,  in  comparing  the 
experiments  with  himself  on  the  treadmill  and  while  walking  on  the 
Neuwaldegg  outside  of  Vienna,  that  the  walking  on  the  treadmill  was 
apparently  done  with  less  expenditure  of  energy  than  walking  in  the 
open.  He  also  finds  that,  within  the  speeds  walked,  the  rate  of  walking 
had  but  slight  effect  on  the  metabolism  per  kilogrammeter.  He  was 

1  Grade  on  treadmill:  Kolmer,  18.2  p.  ct.;  Muller,  2d  period,  26.2  p.  ct. ;  Durig,  2d  period,  14.7 
p.  ct. ;  Zuntz,  on  Monte  Rosa,  grade,  28.8  p.  ct. 

'Durig,  Denkschr.  d.  math.-natur.  Klasse  d.  kaiserl.  Akad.  d.  Wissensch.,  1909,  86,  p.  294. 


12  METABOLISM   DURING  WALKING. 

unable  to  detect  any  increasing  effect  of  the  grade,  but  the  condition 
of  the  path  had  a  marked  effect  in  lessening  the  efficiency.  Durig 
lays  considerable  emphasis  in  this  report  upon  the  question  of  the 
basal  value  to  be  used.  He  questions  the  correctness  of  the  procedure 
of  deducting  a  value  for  a  horizontal  component  based  upon  results 
found  in  horizontal-walking  experiments,  which  necessarily  assumes 
that  the  expenditure  of  raising  the  body  at  each  step  in  horizontal 
walking  is  the  same  as  for  grade  walking,  although  he  computed  the 
energy  cost  for  grade  walking  by  this  method.  Undoubtedly,  as 
Durig  suggests,  the  greatest  error  in  all  the  efforts  to  study  the  energy 
cost  per  kilogrammeter  of  grade-lift  lies  in  assessing  the  value  for  the 
horizontal  component. 

A  comprehensive  and  thorough  study  of  the  energy  expenditures  of 
grade  walking,  per  se,  was  carried  out  by  Brezina  and  Kolmer1  in 
Durig's  laboratory  with  a  motor-driven  treadmill  which  could  be 
adjusted  to  various  grades  and  speeds.  In  addition  to  the  level 
walking  experiments,  experiments  were  made  with  the  subject  walk- 
ing on  grades  of  4.7,  10.0  (ca.),  18  (ca.),  27.9,  35  (ca.),  39,  and  42  per 
cent,  while  the  total  weights  moved,  including  loads,  were  70,  84,  93, 
104,  114,  and  124  kg.  The  speed  of  walking  varied  with  the  grade 
and  the  load,  but  the  range  was  approximately  18  to  45  meters  per 
minute.  Naturally  the  lowest  speeds  were  used  on  the  higher  grades. 
The  method  used  in  determining  the  basal  metabolism  was  that  of 
Zuntz,  but  the  gas-meter  was  not  carried  on  the  back.  The  experi- 
ments were  made  with  Brezina  as  the  subject  and  in  the  forenoon, 
1%  hours  after  a  breakfast  consisting  only  of  a  cup  of  sweetened  tea. 
In  the  calculation  of  the  results,  an  average  basal  metabolism  of  1,083 
gram-calories  per  minute  was  deducted,  this  being  derived  from  earlier 
experiments  with  Brezina.  For  the  level  walking  they  found  an 
average  value  of  0.51  gram-calorie  per  horizontal  kilogrammeter.  The 
maximum  amount  of  work  done  was  at  a  grade  of  27.9  per  cent,  when 
a  weight  of  104.5  kg.  was  moved  at  a  speed  of  about  30  meters  per 
minute.  This  produced  900  kg.  m.  of  work,  with  an  energy  output 
above  the  basal  of  10,000  gram-calories  per  minute.  Brezina  and 
Kolmer  found  a  considerable  variation  in  the  respiratory  quotients, 
but  on  the  whole  the  increases  obtained  depended  upon  the  amount  of 
work  done.  In  the  experiments  when  the  larger  amounts  of  work 
were  performed,  the  respiratory  quotient  was  found  to  be  as  high  as 
0.98  and  there  were  many  experiments  with  a  quotient  over  0.95. 

The  results  of  Brezina  and  Kolmer  are  further  discussed  by  Brezina 
and  Reichel,2  who  consider  the  data  from  a  mathematical  standpoint. 
These  authors  had  previously  shown3  that  the  energy  factor  for  the 

Brezina  and  Kolmer,  Biochem.  Zeitschr.,  1914,  65,  p.  16. 
2Brezina  and  Reichel,  Biochem.  Zeitschr.,  1914,  65,  p.  35. 
*Ibid.,  63,  p.  170. 


RESEARCHES    BY    OTHER   INVESTIGATORS.  13 

movement  of  1  kg.  1  meter  in  horizontal  walking  within  the  range  of 
the  maximal  economic  velocity  was  not  materially  affected  by  loads 
up  to  36  kg.  and  had  derived  a  formula  to  express  this  generalization. 
Assuming  that,  according  to  their  findings,  the  metabolism  per  hori- 
zontal kilogrammeter  is  independent  of  the  speed  and  that  the  same 
relation  exists  for  loads  in  grade  walking  as  is  found  in  level  walk- 
ing (an  assumption  which  they  were  not  able  to  confirm),  they  derived 
a  formula  which  they  believe  expresses  in  approximate  form  the  energy 
metabolized  per  kilogrammeter  of  total  weight  and  meter  distance 
covered  between  grades  of  0  and  35  per  cent.  They  find  the  optimum 
condition  to  be  at  a  grade  of  19.8  per  cent,  with  a  load  of  19  kg.,  which 
required  an  expenditure  of  10.1  calories  for  each  kilogrammeter  of 
grade-lift,  or  an  efficiency  of  23.1  per  cent.  It  should  be  mentioned 
in  this  connection  that  Brezina  and  Reichel  do  not  obtain  net  effi- 
ciencies, since  they  do  not  deduct  the  energy  for  the  horizontal  com- 
ponent, but  compute  the  energy  from  the  heat  expended  over  the  lying 
requirements. 

Brezina  and  Reichel  find  that  for  the  limited  speeds  used  the  rate  of 
walking  was  without  influence  upon  the  energy  per  kilogrammeter, 
and  also  that  the  total  energy  per  kilogrammeter  of  grade-lift 
for  grades  between  10  and  40  per  cent  with  superimposed  loads 
of  from  3  to  56  kg.  varied  from  10.1  (the  optimum  value)  to  12.4 
calories,  while  for  lower  grades  of  2.5  to  7.5  per  cent,  the  measure- 
ments were  as  high  as  29.3  calories.  This  large  difference  was  un- 
doubtedly due  to  the  fact  that  the  work  at  these  low  grades  was  too 
small  a  proportion  of  the  total  energy  metabolized  to  be  accurately 
determined.  Brezina  and  Reichel  give  the  data  somewhat  extensive 
mathematical  treatment  and  derive  certain  formulae  which,  in  their 
judgment,  make  it  possible  to  calculate  the  increase  in  energy  due  to 
the  load  and  the  grade,  provided  certain  limits  of  speed  and  load  are  not 
overlooked.  They  likewise  include  the  efficiency  as  a  constant  function 
of  the  grade. 

The  work  of  Brezina  and  his  associates  Kolmer  and  Reichel  is  by 
far  the  most  extensive  and  painstaking  of  any  of  the  studies  on  the 
physiology  of  walking,  and  their  conclusions  are  suggestive.  But, 
as  they  themselves  say,  though  the  study  was  carried  out  over  a 
considerable  range  of  speed  and  grade,  the  data  represent  the  results 
of  experiments  with  only  one  subject  and  considerably  more  data  are 
required  before  their  generalizations  can  be  universally  accepted. 

In  physiological  experimenting  the  use  of  but  one  subject  has  fre- 
quently been  the  basis  of  much  adverse  criticism  of  a  piece  of  work. 
It  is  true  that  if  but  one  isolated  physiological  factor  is  to  be  measured, 
this  criticism  is  a  serious  one.  In  a  study  in  which  so  complicated  a 
process  as  the  energy  requirements  of  walking  is  concerned,  the  results 
of  a  careful  series  of  experiments  like  those  of  Brezina  and  Kolmer, 


14  METABOLISM   DURING   WALKING. 

even  when  but  one  man  is  used  for  a  subject,  may  properly  be  employed 
for  extensive  generalizations,  until  deviations  with  other  subjects  are 
proved.  While,  therefore,  we  are  in  full  accord  with  the  criticisms 
of  Cathcart,  Lothian,  and  Greenwood,  previously  referred  to,  we  still 
are  disposed  to  consider  a  series  of  experiments,  such  as  those  made 
with  Brezina,  of  most  fundamental  importance  in  the  progress  of  our 
knowledge  of  the  physiology  of  walking.  Indeed,  in  our  experiments 
the  importance  of  contributing  further  observations  on  a  number  of 
individuals  has  played  a  not  unimportant  r61e  in  planning  the  research. 

Although  Amar1  reported  a  number  of  experiments  in  which  the 
subject  was  engaged  in  horizontal  walking,  we  have  found  hi  his  studies 
but  two  with  grade  walking.  These  were  made  with  one  subject 
walking  on  an  8  per  cent  grade  and  again  on  a  13  per  cent  grade, 
with  and  without  a  superimposed  load  of  7.3  kg.  The  experiments 
are  but  briefly  reported  and  the  data  do  not  lend  themselves  to  an 
extensive  computation  of  the  efficiency. 

In  1912,  Douglas,  Haldane,  Henderson,  and  Schneider,*  in  an 
expedition  to  Pike's  Peak,  made  an  extensive  series  of  horizontal- 
walking  experiments  which  included  two  grade-walking  observations, 
in  which  the  gradient  was  1  in  4,  and  the  speed  from  2  to  2.25  miles 
per  hour.  The  special  conditions  of  altitude,  diet,  and  terrain  make  the 
results  difficult  of  comparison  with  others. 

Waller3  has  made  some  estimates  of  the  mechanical  efficiency  shown 
by  men  in  ascending  a  staircase  while  breathing  into  a  Douglas  bag. 
The  total  volume  of  air  exhaled  and  the  carbon  dioxide  produced  were 
determined  in  these  experiments.  By  assuming  a  respiratory  quotient 
of  0.85,  Waller  computed  the  energy  expended  during  the  work  and 
believes  that  =*=  5  per  cent  was  the  range  of  «error  by  this  method.  He 
reports  data  for  12  subjects  varying  in  age  from  18.5  to  63  years  and 
in  weight  from  54.5  to  98  kg.,  who  made  the  ascent  of  a  20-meter  stair- 
case at  an  average  efficiency  of  33  per  cent. 

Waller  and  de  Decker4  report  an  average  mechanical  efficiency  of 
32  per  cent  for  T.  R.  P.  in  five  ascents  of  the  staircase.  Later,  in  a 
comparison  of  bicycle  with  staircase  ergometry,5  17  experiments  with 
A.  D.  W.  showed  efficiencies  varying  from  24.8  to  41.6  per  cent  for 
the  staircase  work.  A  complete  report  of  this  work  of  Waller  has  not 
yet  appeared,  but  the  results  thus  far  published  indicate  very  wide 
variations. 

Magne6  has  recently  made  a  study  of  the  changes  in  the  energy 

'Amar,  Le  moteur  humain,  Paris,  1914,  p.  507. 

2Douglas,  Haldane,  Henderson,  and  Schneider,  Phil.  Trans.  Roy.  Soc.  London,  1913,  ser.  B, 
203,  p.  185. 

"Waller,  Journ.  Physiol.,  Proc.  Physiol.  Soc.,  1919,  52,  p.  Ixxii. 

4Waller  and  de  Decker,  Journ.  Physiol.,  Proc.  Physiol.  Soc.,  1919,  53,  p.  xxx. 

6 Ibid.,  p.  xliv. 

'Magne,  Journ.  de  physiol.  et  de  path,  gen.,  1920,  18,  p.  1154. 


RESEARCHES   BY    OTHER   INVESTIGATORS.  15 

expenditure  in  walking  due  to  alterations  in  the  number  and  length 
of  the  steps.  By  means  of  a  rubber  bag  and  a  Tissot  mask,  the  air 
expired  during  the  experimental  period  was  collected  and  samples 
analyzed.  The  subject  was  in  the  post-absorptive  condition  and 
walked  with  a  carefully  controlled  frequency  and  length  of  step  both  on 
a  level  and  on  grades  of  approximately  5,  10,  and  15  per  cent.  Magne 
found  that  the  minimum  net  expenditure  for  a  given  distance  on  a 
level  was  obtained  at  an  approximate  speed  of  63  meters  per  minute, 
and  the  average  net  efficiency  for  the  grade  experiments  was  not  far 
from  20  per  cent. 

GENERAL  CONSIDERATIONS  WITH  REGARD  TO  PREVIOUS  WORK  ON  GRADE 

WALKING. 

The  technical  difficulties  necessary  to  be  overcome  in  a  study  of 
grade  walking  are  so  great  that  only  those  who  have  had  actual  ex- 
perience hi  such  experiments  are  in  a  position  to  criticize  fairly  the 
work  of  others.  The  historical  development  of  the  method  of  studying 
metabolism  during  severe  muscular  work,  not  only  that  of  walking  but 
likewise  of  other  forms,  such  as  bicycle  riding,  has  gradually  led  to  a 
perfection  of  the  technique.  In  reviewing  the  earlier  work,  it  is 
noticeable  that  the  criticism  that  applied  to  the  horizontal-walking 
experiments  applies  with  even  greater  force  here,  namely,  that  it 
became  necessary  in  many  series  of  experiments  to  work  under  some- 
what disadvantageous  conditions. 

The  dry  gas-meter  method,  which  has  been  used  in  so  large  a  pro- 
portion of  the  earlier  studies,  has  one  great  disadvantage  in  that  no 
experiments  can  be  made  without  a  load.  The  carrying  of  a  pack  is 
to  be  expected  in  walking,  and  particularly  in  Alpine  work,  but  the 
transportation  of  an  apparatus  such  as  a  gas-meter  and  accessories, 
weighing  many  kilograms  and  attached  to  the  back,  even  though  in 
the  most  approved  manner,  still  presents  a  problem  in  equilibrium 
that  is  attained  only  with  considerable  practice.  While  it  is  true  that 
the  transportation  of  loads  is  of  great  economic  importance  in  indus- 
trial operations,  and  a  knowledge  of  the  efficiency  in  transporting 
loads  is  thus  essential,  yet  thousands  of  people  walk  each  day  without 
a  load  in  comparison  with  the  individual  with  a  load;  consequently, 
observations  which  can  be  obtained  on  individuals  not  carrying  loads 
are,  we  believe,  of  general  interest. 

The  modern  method  of  substituting  either  a  Douglas  bag  or  a 
treadmill  with  a  stationary  meter  is  much  to  be  preferred  to  the  gas- 
meter  method,  provided  essential  differences  between  the  work  of 
walking  in  a  well-ventilated  room  and  that  of  walking  in  the  free  and 
open  air  on  an  equally  even  or  satisfactory  path  are  not  subsequently 
developed.  The  Douglas-bag  method  is  certainly  a  step  in  the  right 


16  METABOLISM   DURING   WALKING. 

direction,  inasmuch  as  the  load  is  almost  imperceptible.  Unfortu- 
nately, relatively  few  experiments  have  as  yet  been  carried  out  with 
this  method,  and  many  of  these  have  been  hastily  made  and  without 
the  careful  attention  to  technical  detail  given  in  experiments  with  other 
types  of  apparatus. 

Our  own  justification  for  making  a  study  of  the  respiratory  exchange 
in  grade  walking  was,  as  stated  earlier,  the  fact  that  it  should  serve  in 
large  part  as  a  preliminary  to  a  research  upon  grade  walking  in  which 
direct  calorimetry  would  be  employed.  The  pronounced  alterations 
in  the  respiratory  quotient  with  severe  labor,  resulting  in  quotients 
at  times  appreciably  over  1.00,  make  it  a  fair  question  as  to  whether 
or  not  the  methods  of  indirect  calorimetry  give  true  indices  of  the 
actual  heat-production  under  these  conditions.  Admittedly,  the 
technical  details  to  be  overcome  in  making  a  study  by  direct  calori- 
metry of  the  energy  output  of  a  man  walking  nearly  to  the  limit  of 
human  endurance  are  very  great,  but  it  is  believed  that  they  may  be 
overcome.  In  an  effort  to  improve  much  of  this  technique,  prior 
to  inclosing  the  man  in  a  hermetically  sealed  chamber,  the  treadmill 
experiments  reported  in  the  following  pages  were  carried  out  at  the 
Nutrition  Laboratory. 

PLAN  OF  STUDY. 

The  primary  object  of  the  experiments  in  this  research  was  the 
determination  of  the  energy  expended  by  the  human  body  in  perform- 
ing the  work  of  lifting  itself  to  a  definite  elevation  by  walking  up-grade. 
With  a  treadmill  of  unusual  design  and  accuracy,  a  respiration  appa- 
ratus capable  of  measuring  an  oxygen  consumption  of  3,000  c.  c.  per 
minute  and  over  with  great  rapidity  and  exactness,  much  accessory 
apparatus  for  studying  physiological  factors,  such  as  respiratory 
volume,  respiration-rate,  pulse-rate,  step-lift,  etc.,  it  was  believed  that 
opportunity  was  afforded  for  a  contribution  to  the  general  physiology 
of  horizontal  walking,  also,  which  would  amply  justify  the  additional 
labor.  As  previously  stated,  it  was  at  the  outset  considered  that  this 
whole  research  was  preliminary  to  a  subsequent  study  in  which 
direct  calorimetry  would  be  employed. 

The  total  energy  that  is  expended  by  the  human  body  during 
grade  walking  is  the  sum  of  several  factors,  among  which  are  (1)  the 
energy  required  to  maintain  the  vital  functions,  such  as  respiration  and 
circulation,  while  the  body  is  at  rest,  which  may  be  termed  basal 
energy;  (2)  the  energy  required  for  the  muscular  movements  of  the 
simple  act  of  walking  on  a  level;  (3)  the  energy  required  to  lift  the 
body  through  a  vertical  distance  corresponding  to  the  elevation 
attained  in  the  grade  walking.  Since  the  measurements  of  the  metab- 


PLAN   OF   STUDY.  17 

olism  in  the  grade-walking  experiments  reported  in  this  publication 
represented  the  total  energy  expended,  it  was  necessary  to  know  both 
the  basal-energy  cost  and  the  cost  of  horizontal  walking  to  obtain  the 
energy  cost  of  the  work  of  elevation. 

Three  groups  of  experiments  were  therefore  carried  out:  (1)  standing 
experiments,  in  which  determinations  were  made  of  the  energy  ex- 
pended while  the  subject  was  standing  quietly  without  support,  these 
values  being  taken  in  the  computations  as  the  "rest"  requirement; 
(2)  horizontal-walking  experiments  with  measurements  of  the  energy 
output  at  different  speeds  of  walking;  from  these  the  energy  expended 
hi  excess  of  the  "rest"  requirement  was  found,  and  thus  the  cost  of 
moving  1  kg.  of  body-weight  1  meter  on  a  level  was  determined;  (3) 
grade-walking  experiments  from  which  the  energy  expended  per  kilo- 
grammeter  of  vertical  lift  in  excess  of  the  rest  and  horizontal-walking 
requirements  was  calculated  for  the  different  grades  and  speeds  with 
the  efficiencies  for  each  condition. 

It  was  the  intention  to  have  the  subject  walk  at  certain  definite  rates 
in  order  that  level  and  grade  walking  might  be  compared  at  the  same 
speeds.  Technical  difficulties  in  the  precise  regulation  of  the  speed  of 
the  treadmill  made  strict  duplication  too  exacting  a  task  in  many 
instances  and  the  results  are  consequently  grouped  according  to  the 
speeds  which  fell  within  limits  of  5  meters  per  minute  of  each  other. 
The  grades  were  more  easily  maintained  in  the  range  between  2.5  to 
45  per  cent  in  rates  of  5  per  cent  increase.  It  would  have  been  desirable 
to  have  made  both  standing  and  horizontal-walking  tests  on  each  day 
that  the  grade- walking  experiments  were  made;  since,  however,  it  was 
impossible  to  make  experiments  with  a  sufficient  number  of  periods  in 
each  of  the  three  groups,  the  only  alternative  was  to  secure  an  average 
value  for  both  the  standing  and  the  horizontal-walking  experiments. 

The  data  obtained  during  the  horizontal-walking  experiments,  besides 
supplying  the  energy  factor  per  horizontal  kilogrammeter  used  in  com- 
puting the  energy  to  be  deducted  from  the  values  for  the  grade-walking 
experiments,  allow  a  comparison  of  this  factor  with  that  reported  by 
other  investigators,  and  we  believe  they  present  in  themselves  a  sub- 
stantial addition  to  our  knowledge  of  the  physiology  of  walking.  They 
also  provide  additional  information  as  to  the  effect  of  the  speed  of 
walking  upon  the  energy  required  per  horizontal  kilogrammeter,  which 
has  been  reported  to  be  practically  independent  of  the  speed  for  rates 
less  than  80  meters  per  minute. 

Another  element  contributing  to  the  work  performed  in  either 
horizontal  or  grade  walking  in  addition  to  the  three  factors  previously 
mentioned  is  the  elevation  of  the  center  of  gravity  of  the  body  as  it 
moves  forward  with  each  step.  This  elevation  of  the  body  represents 
a  positive  and  appreciable  amount  of  work.  An  effort  has  been  made 


18  METABOLISM   DURING   WALKING. 

to  determine  this  elevation,  or  "step-lift,"  and  to  express  it  in  terms  of 
kilogrammeters  of  work.  The  proportion  of  increase  in  the  energy 
due  to  this  factor  in  horizontal  walking  may  thus  be  obtained.  If,  in 
the  grade  experiments,  the  work  due  to  the  step-lift  is  added  to  the 
work  of  the  vertical  lift  of  the  grade,  the  sum  represents  what  may  be 
called  the  total  "work  of  ascent." 

In  addition  to  these  primary  measurements,  the  experimental  con- 
ditions were  favorable  for  collecting  data  on  other  physiological 
factors,  and  some  results  are  presented  on  the  changes  in  the  respira- 
tion-rate and  pulse-rate,  the  pulmonary  ventilation,  and  rectal  body- 
temperature  which  accompany  the  changes  hi  the  amount  of  work 
performed.  A  few  observations  on  the  changes  in  the  blood-pressure 
between  rest  and  exercise  were  made  for  comparison  with  the  changes 
in  the  amount  of  work  being  done. 

The  readiness  with  which  the  heart  and  lungs  respond  to  the  chang- 
ing demand  of  the  body  when  work  was  either  begun  or  ceased  was  also 
studied.  The  adaptability  of  the  body  to  new  demands — at  times,  a 
demand  approximating  the  limit  of  human  endurance,  necessitating 
an  oxygen  consumption  of  over  3,000  c.  c.  per  minute — is  a  factor  in 
human  economy  that  has  been  hitherto  too  little  studied.  The 
rapidity  of  adjustment  after  most  strenuous  exercise  is  of  utmost 
importance  in  estimating  "fitness"  for  the  work  performed.  These 
experiments  have  been  referred  to  as  "transitional"  experiments,  and 
by  measuring  the  oxygen  consumption,  ventilation,  pulse-rate,  and 
respiration-rate  for  successive  fractions  of  a  minute  until  either  the 
normal  or  an  approximately  constant  rate  was  obtained,  the  relation 
between  the  response  of  these  physiological  processes  to  the  amount  of 
work  performed  was  obtained. 


METHODS  OF  MEASUREMENT. 

The  group  of  apparatus  used  in  this  research  was,  in  principle,  that 
employed  and  described  by  Benedict  and  Murschhauser,1  but  with 
modifications  essential  for  the  increased  amount  of  work  to  be  per- 
formed. The  principal  apparatus  employed  were  the  universal  res- 
piration apparatus  for  determining  the  gaseous  metabolism  and  the 
treadmill  for  the  measurement  of  the  muscular  work.  In  addition, 
accessory  apparatus  were  used  for  securing  data  on  the  pulse-rate, 
pulmonary  ventilation,  body-temperature,  etc.,  which  were  not 
obtained  by  Benedict  and  Murschhauser  in  their  study.  The  general 
arrangement  of  the  apparatus,  with  subject  in  position  for  an  actual 
experiment,  is  shown  in  the  frontispiece  and,  in  part,  in  figure  1. 

Benedict  and  Murschhauser,  Carnegie  Inst.  Wash.  Pub.  No.  231,  1915,  p.  29. 


METHODS   OF   MEASUREMENT.  19 

A  n T- 


FIG.  1. — Treadmill,  with  spirometer  and  various  recording  devices. 

The  circulating  air  from  the  soda-lime  containers  of  the  respiration  apparatus  was  conducted  to 
the  subject  through  the  pipe  A,  and  after  passing  through  the  pipes  E  and  F  and  the  spir- 
ometer G,  was  returned  to  the  absorbers  through  the  pipe  H.  Preliminary  to  the  experi- 
ment, the  subject  respired  into  the  room  air  through  the  3-way  valve  D  by  the  port  d.  At 
the  beginning  of  the  period,  the  valve  D  was  turned  and  the  subject  was  connected  with  the 
circulating-air  system.  By  means  of  the  by-pass  B,  the  circulating  air  could  be  deflected 
through  C  and  brought  closer  to  the  mouth  of  the  subject,  thus  eliminating  rebreathing. 
The  parts  of  the  apparatus  specially  indicated  in  the  figure  are:  E,  rubber  hose  to  permit  the 
adjustment  of  the  mouthpiece  to  any  height  needed  by  the  subject;  G,  spirometer  with 
ventilation  adder-wheel  w  and  kymograph  Z;  g,  pulley  for  reducing  the  movement  of  the 
pointer  recording  on  the  kymograph  drum;  7,  lever  for  operating  valve  D  by  the  bar  /, 
connected  by  cord  with  arm  k;  L,  knob  supporting  the  arm  K;  M,  tension  spring  for  operating 
valve  D;  N,  NI,  screws  for  adjusting  the  grade  of  the  treadmill;  O,  spirit-level;  P,  motor, 
driving  mechanism  not  shown;  Q,  Qi,  adjustable  brake  on  the  motor  shaft;  R,  counter  for 
recording  revolutions  of  front  pulley;  S,  long  wooden  fork  fastened  to  the  shoulders  of  the 
subject  by  elastic  webbing;  the  rise  and  fall  of  this  fork  is  transmitted  by  T  to  the  step-lift 
counter  and  kymograph,  not  shown  in  the  drawing;  U,  U\,  electrodes  for  securing  electro- 
cardiograms of  the  pulse-rate;  V,  electrode  for  grounding  the  subject;  W,  W\,  brass-gauze 
brush  and  leads  for  grounding  the  treadmill;  this  brush  was  discarded  when  the  method  was 
changed  to  that  of  grounding  the  subject  by  the  electrode  V;  X,  step-counter  with  spring 
attached  to  the  subject's  ankle;  Y,  framework  protecting  the  spirometer. 


20  METABOLISM   DURING   WALKING. 

UNIVERSAL  RESPIRATION  APPARATUS. 

The  universal  respiration  apparatus  in  its  various  adaptations  has 
been  frequently  described  in  the  publications  from  this  Laboratory.1 
Briefly  stated,  it  consists  of  a  closed  ventilating  air-circuit,  with  pro- 
visions for  a  moderate  deigrete  of  expansion  in  the  air-volume  and  con- 
nection with  the  subject  by  means  of  a  mouthpiece  or  nosepiece.  The 
air  is  kept  in  motion  by  a  rotating  ventilator  or  blower,  actuated  by  an 
electric  motor,  which  forces  the  expired  air  through  absorbents  for 
moisture  and  carbon  dioxide  arid,  returns  it  to  the  subject  for  rebrejath- 
ing  aftetr  the  air  has  been  moistened  and  the  oxygen  dejficit  has  been 
made  up  from  an  oxygen-supply  connected  with  the  system  and 
metored.  Sulphuric  acid  is  used  for  the  water-absorbent  and  moist 
soda-lime  for  the  carbon-dioxide  absorbent.  The  combined  increase  in 
the  weight  of  the  soda-lime  containers  and  the  supplementary  watdr- 
absorbe^1  gives  data  fojr  calculating  the  volume  of  carbon  dioxide 
expired  by  the  subject.  The  amount  of  oxygen  consumed  is  deter- 
mined from  the  readings  of  a  calibrated  integrating  meter  connected 
with  the  oxygen-supply.  The  absorbing  system,  mounted  on  a  two- 
shelved  table,  is  in  duplicate,  with  suitable  valve  connections  which 
permit  the  use  of  either  series  of  absorbers  at  will. 

Since  the  amount  of  work  to  be  performed  was  greater  than  in  the 
study  made  by  Benedict  and  Murschhauser,  the  ventilating  system  was 
equipped  with  a  larger  motor  and  driving-pulley.  The  speed  of  the 
one-sixth  horse-power  electric  motor  employed  was  controlled  by  a 
rheostat,  fixed  upon  the  front  of  the  table,  which  permitted  the  varia- 
tion of  the  ventilating  air-current  between  65  and  100  liters  per  minute. 
The  two  sulphuric-acid  containers,  or  "Williams  bottles,"  which  were 
inserted  in  the  system  next  to  the  blower,  each  had  a  capacity  of  2.5 
liters  and  were  followed  by  a  train  of  two  large  soda-lime  containers 
for  the  absorption  of  the  carbon  dioxide,  and  a  third  large  Williams 
bottle  or  air-drier  for  absorbing  any  moisture  carried  over  from  the 
moist  soda-lime. 

Moistener. — The  dry  air,  after  it  left  the  carbon-dioxide  absorbers, 
was  moistened  by  passing  it  through  water  contained  in  a  large  Williams 
bottle.  None  of  the  subjects  complained  that  the  ah*  was  too  dry.  A 
test  was  made  of  the  percentage  of  humidity  by  inserting  a  psychro- 
meter  in  the  air-circuit,  and  an  average  figure  of  70  per  cent  was  found 
when  the  rate  of  ventilation  was  highest.  This  figure  has  been  used 
hi  reducing  the  volume  of  the  pulmonary  ventilation  to  standard 
conditions. 

Spirometer. — In  the  research  of  Benedict  and  Murschhauser,  a 
rubber  bathing-cap  was  used  as  a  tension  equalizer  for  fluctuations 

Benedict,  Deutsch.  Archiv  f.  klin.  Med.,  1912,  107,  p.  156;  Benedict  and  Cathcart,  Carnegie 
Inst.  Wash.  Pub.  No.  187,  1913,  p.  27;  Benedict  and  Murschhauser,  Carnegie  Inst.  Wash.  Pub. 
No.  231,  1915,  p.  31;  Carpenter,  Carnegie  Inst.  Wash.  Pub.  No.  216,  1915,  p.  21. 


METHODS   OF   MEASUREMENT.  21 

in  the  volume  of  air  in  the  closed  circuit.1  In  the  present  research, 
a  large  spirometer  (G  in  figure  1)  was  employed,  8  liters  in  capacity, 
which  was  built  on  the  principles  already  described  in  reports  from  this 
Laboratory.2  This  spirometer  was  placed  on  a  small  table  at  the  left 
of  the  treadmill  and  close  to  the  subject.  A  light,  non- viscous  oil  was 
used  in  the  spirometer  rather  than  water.  None  of  the  subjects  com- 
plained of  odor  from  the  oil;  in  fact,  none  of  them  knew  that  oil  was 
used. 

During  the  experiments,  when  severe  muscular  work  was  being 
performed,  the  respirations  of  the  subject  became  so  deep  that  the 
movements  of  the  spirometer-bell  were  too  large  to  be  recorded  on  the 
usual  kymograph-drum.  To  reduce  the  movement  of  the  pointer, 
the  thread  supporting  the  bell  was  passed  through  a  pulley  to  which 
the  counterpoise  and  the  pointer  were  attached.  (See  g,  fig.  1.)  The 
movement  of  the  pointer  was  thus  reduced  one-half,  but  this  had  its 
disadvantage  in  that  it  doubled  any  error  in  the  reading,  since  all 
readings  must  be  multiplied  by  2.  As  in  the  walking  experiments, 
the  oxygen  consumption  was  frequently  8  to  10  times  the  resting  value, 
this  doubling  of  the  error  played  no  role  save  in  the  "rest"  experiments. 

In  measuring  the  rate  of  oxygen  consumption  in  certain  tests  in  this 
research,  no  oxygen  was  admitted  for  a  portion  of  the  experimental 
period  and  the  lower  capacity  limit  of  the  spirometer  was  thus  reached 
in  a  few  minutes.  For  these  few  tests,  use  was  made  of  the  double 
spirometer  shown  in  figure  2.  A  duplicate  spirometer  A  is  attached  to 
the  principal  one  B  by  a  large  tube  E  and  a  3-way  valve  D.  The 
oxygen  is  introduced  by  means  of  the  connection  (7.  Both  spirometers 
were  filled  with  pure  oxygen  before  an  experiment,  and  the  usual 
readings  taken  on  the  main  spirometer  B.  As  soon  as  the  subject  was 
connected  with  the  ventilating  system,  the  bell  of  the  spirometer  B 
fell  rapidly  with  each  respiration  as  the  oxygen  was  consumed.  When 
the  oxygen  was  at  as  low  a  level  as  seemed  wise,  the  three-way  valve  D 
was  opened  and  oxygen  from  the  duplicate  spirometer  A  was  forced 
into  B  by  pushing  down  the  bell  of  A.  The  valve  was  then  closed 
and  A  was  again  filled  from  the  oxygen  cylinder  through  the  connec- 
tion C.  This  was  repeated  as  often  as  necessary.  The  kymograph 
curve  thus  shows  a  succession  of  hills  and  valleys  (see  fig.  15,  p.  183), 
due  to  the  fact  that  the  pointer  rose  on  the  scale  of  B  as  the  oxygen 
was  consumed  and  then  sank  when  the  supply  from  the  reservoir  A 
was  forced  into  the  main  spirometer  B.  The  time  of  filling  spirometer 
B  was  scarcely  2  seconds,  and  not  over  one  or  two  respiration  tracings 
were  lost  in  the  process. 

Benedict,  Am.  Journ.  Physiol.,  1909,  24,  p.  345.  See,  also,  Carpenter,  Carnegie  Inst.  Wash. 
Pub.  No.  216,  1915,  p.  24. 

2Benedict,  Deutsch.  Archiv  f.  klin.  Med.,  1912,  107,  p.  172;  Carpenter,  Carnegie  Inst.  Wash. 
Pub.  No.  216,  1915,  p.  37. 


22 


METABOLISM   DURING   WALKING. 


Pressure  conditions. — The  large  volume 
of  air  being  forced  through  the  air-puri- 
fying system  by  .the  rapidly  moving 
blower  created  considerable  pressure  in 
the  system,  and  a  small  mercury  mano- 
meter was  introduced  at  the  head  of  the 
absorber  table  immediately  in  front  of 
the  soda-lime  bottles  to  act  as  a  safety- 
valve  in  case  of  need.  The  pressure  indi- 
cated by  this  manometer  when  the  blower 
was  delivering  air  at  the  rate  of  100  liters 
per  minute  was  from  130  to  180  mm.  of 
mercury,  depending  upon  the  condition  of 
the  soda-lime  and  the  amount  of  acid  in 
the  Williams  bottles.  From  the  absorber 
table  to  the  valve  of  the  mouthpiece,  a 
f-inch  galvanized-iron  pipe  was  used  and 
all  joints,  where  practical,  were  soldered 
to  reduce  possibilities  of  leaks  when  there 
was  a  high  pressure  on  the  system.  On 
the  return  line  from  the  valve  to  the  spiro- 
meter  (see  F,  fig.  1)  the  pipe  was  6  cm.  in 
diameter,  ordinary  galvanized-iron  con- 
ductor-pipe being  used  for  the  most  part. 
This  reduced  the  pressure  so  that  just 
beyond  the  mouthpiece  water  manome- 
ters showed  a  variation  in  pressure  of  but  2  to  10  mm.  of  water,  and 
the  opening  of  a  petcock  under  the  spirometer  had  scarcely  any  effect 
on  the  position  of  the  bell,  so  evenly  balanced  was  the  pressure. 

Adjustment  to  subject. — To  permit  raising  and  lowering  the  con- 
nections with  the  subject  on  the  treadmill,  a  2-foot  length  of  corru- 
gated flexible  metal  tubing  was  introduced  on  one  side  and  on  the 
opposite  side  a  rubber  hose  was  inserted  (E,  fig.  1),  5  cm.  in  diameter, 
of  about  the  same  length  as  the  metal  tubing.  This  permitted  the  nec- 
essary up-and-down  adjustment  to  the  height  of  the  subject  and  the 
pitch  of  the  treadmill.  For  conducting  the  air  from  the  spirometer  to 
the  absorber  table,  rubber  tubing  28  mm.  in  diameter  was  used. 

Meter. — An  integrating  meter,1  capable  of  being  read  to  10  c.  c., 
was  used  for  measuring  the  oxygen  consumption.  As  the  experimental 
periods  seldom  exceeded  12  minutes  and  the  room  temperature  was 
fairly  uniform,  temperature  changes  were  for  the  most  part  insignifi- 
cant, though  always  measured.  The  meter  was  equipped  with  an 

JThe  meter  used  was  made  by  the  American  Meter  Company,  New  York,  N.  Y.,  their  0.1 
cu.  ft.  wet  test  meter  (No.  613),  fitted  with  dial  to  read  in  liters.  One  revolution  is  equivalent  to 
3  liters,  the  total  reading  will  run  to  1,000  liters,  and  the  volumes  may  be  read  to  10  c.  c. 


FIQ.  2. — Double  epirometer. 
B,  main  spirometer;  A,  duplicate 
spirometer  used  as  reservoir;  C, 
connection  with  oxygen-supply ;  D, 
three-way  valve  between  A  and  B; 
E,  rubber  tubing  connecting  A 
and-B. 


METHODS   OF   MEASUREMENT.  23 

accurate  thermometer,  which  was  read  at  the  beginning  and  end  of 
each  experiment.  The  average  of  these  readings  was  used  for  the 
slight  correction  of  the  volume  of  oxygen  due  to  temperature  changes 
of  the  meter.  The  meter  was  calibrated1  by  passing  weighed  amounts 
of  oxygen  through  it  at  various  rates,  and  the  factors  thus  obtained 
were  used  in  all  subsequent  computations.  Several  calibrations  were 
made  during  the  course  of  the  investigation  with  approximately  uni- 
form results,  which  were  but  the  fraction  of  1  per  cent  high.  This 
meter  proved  very  satisfactory,  especially  the  integrating  feature, 
which  eliminated  the  danger,  ever-present  with  other  types  of  meters, 
of  failure  to  record  accurately  the  total  number  of  revolutions  of  the 
pointer.  The  oxygen  used  in  the  experiments  was  made  and  supplied 
by  the  Linde  Air  Products  Company. 

Barometer. — In  the  12-minute  periods  of  this  research  the  barometric 
changes  under  ordinary  atmospheric  conditions  were  almost  negligible. 
For  measuring  such  changes  a  barograph  was  used,  checked  by  a  re- 
liable barometer,  and  read  to  0.1  mm.  These  readings  were  made  at 
the  beginning  and  end  of  each  period,  the  average  being  used  for 
reducing  the  data  for  the  oxygen  consumption  to  standard  conditions. 

Kymograph. — The  usual  Porter  kymograph2  was  employed,  but  in 
place  of  records  on  smoked  paper,  pen-and-ink  tracings  on  an  unsmoked 
glazed  paper  were  obtained.  The  pen,  which  was  fastened  to  the 
counterpoise  of  the  spirometer-bell,  was  a  small  glass  capillary  pen 
with  platinum  tip,  such  as  is  employed  on  many  forms  of  automatic 
reading  devices  in  large  steam  and  electric  plants.3  This  method  was 
found  to  be  simpler  and  cleaner  than  working  with  smoked  paper  and 
a  varnishing  solution.  The  speed  of  the  kymograph-drum  was 
1  revolution  in  15  minutes.  A  small  pen,  such  as  is  used  with  the 
ordinary  barograph,  was  attached  to  a  signal  magnet  connected  with 
the  clock,  and  a  record  thus  obtained  in  minutes  on  the  glazed  paper. 

Respiration  counter. — The  number  of  respirations  during  the  period 
was  at  first  counted  from  the  tracings  of  the  pen  attached  to  the  spiro- 
meter-beM.  Later  a  device  (see  fig.  3)  was  attached  to  the  arm  of  the 
spirometer  (see  A,  fig.  3).  The  cord  B,  leading  to  the  counterpoise 
of  the  spirometer-bell,  by  rubbing  on  the  fiber  sleeve  C  caused  the 
platinum  points  E  and  E\  to  dip  into  the  mercury  cups  D  and  D\  and 
complete  a  circuit  to  a  counting  device  known  in  the  telephone  trade 
as  a  "p.  b.  x.  message  register."  (See  fig.  4.)  This  device  proved  a 
great  labor-saver  in  counting  the  respiration  tracings  on  the  kymo- 
graph. 

Benedict,  Phys.  Review,  1906,  22,  p.  294. 

^Harvard  Apparatus  Company,  Dover,  Massachusetts. 

The  pen  which  gave  the  most  satisfactory  results  was  the  Cochrane  pen,  supplied  by  the 
Harrison  Safety  Boiler  Company  of  Philadelphia,  Pennsylvania.  It  was  about  40  mm.  long  and 
6  mm.  in  diameter.  With  ordinary  care  the  pen  withstood  a  remarkable  amount  of  use  before 
it  was  worn  out. 


24 


METABOLISM   DURING   WALKING. 


B 


FIG.  3. — Respiration  counter. 

A,  spirometer  frame;  B,  cord  from  spirom- 
eter-bell  leading  to  counterpoise;  C, 
fiber  sleeve;  D,  D\,  mercury  cups;  E, 
Ei,  platinum-pointed  fork  for  com- 
pleting the  circuit  through  D  and 
Di\  F,  stop;  G,  leads  to  electrically 
operated  counter  shown  in  fig.  4. 


Ventilation  recorder. — The  total  volume  of  air  drawn  into  the  lungs 
was  registered  by  means  of  an  attachment  previously  described,1  and 
commonly  referred  to  as  the  "ventilation  adder."  This  consists  of  an 
aluminum  wheel  (w,  fig.  1) 
attached  to  the  apparatus  in 
such  a  manner  that  each  down- 
ward movement  of  the  spirom- 
eter-bell  due  to  inhalation 
by  the  subject  moves  the 
wheel  upward.  By  means  of  a 
signal  magnet,  each  revolution 
of  the  wheel  is  recorded  upon 
the  kymograph.  From  this 
graphic  record  and  the  volume 
corresponding  to  a  revolution 
of  the  wheel,  the  total  inspira- 

tory  Ventilation  Can  be  CalcU-       FlG-  4.— Electrical  counter  for  recording  number  of 
i    A.    j         A     c.      L  j.i_  i  respirations.     For   operating  device  and   con- 

lated.      At  first  the  pulmonary  nections  with  the  apparatus,  see  fig.  3. 

ventilation  during  grade  walk- 
ing was  found  by  actual  measurement  of  the  pen  tracings  on  the  kymo- 
graph, but  later  with  the  ventilation  adder.    The  ventilation  data 
secured  have  been  reduced  to  standard  conditions  for  temperature  and 
pressure  for  recording  in  the  tables. 

Mouthpiece. — The  mouthpiece  used  was  of  the  Denayrouse  type.2 
At  the  beginning  of  the  study  strips  of  surgeon's  plaster  across  the  lips 

^Benedict,  Deutsch.  Archiv  f.  klin.  Med.,  1912,  107,  p.  176;  see  also  Carpenter,  Carnegie  Inst. 
Wash.  Pub.  No.  216,  1915,  p.  40. 

2P.  Regnard,  Recherches  experimentales  sur  les  variations  pathologiques  des  combustions 
respiratorires,  Paris,  1879,  p.  286;  also  Carpenter,  Carnegie  Inst.  Wash.  Pub.  No.  216,  1915, 
p.  54. 


METHODS    OF   MEASUREMENT.  25 

were  used  with  all  the  subjects  to  prevent  possible  leakage  around  the 
mouthpiece,  but  later  these  were  omitted  with  W.  K.  and  E.  D.  B. 
after  they  had  become  accustomed  to  the  conditions.  The  normality 
of  long-continued  breathing  through  the  mouthpiece,  especially  under 
the  conditions  of  the  grade-walking  experiments,  was  tested  in  a  series 
of  experiments.  The  results  of  these  tests  are  discussed  on  page  177. 

The  valve-operating  device. — The  method  of  operating  the  valve  which 
connects  the  subject  with  the  air-circuit  is  shown  in  figure  5,  page  28. 
An  arm  on  the  stem  of  the  valve  is  connected  by  a  cord  F  to  a  bar  K, 
which  is  supported  on  a  button  L.  (See,  also,  fig.  1,  p.  19.)  When  the 
operator  pushes  forward  the  lever  J,  L  is  forced  from  under  the  bar  K 
and  the  tension  of  the  spring  M  turns  the  valve.  Resetting  the  button 
L  and  shifting  the  cord  to  the  other  side  of  the  arm  k  (see  fig.  1)  permit 
the  closing  of  the  valve  at  the  end  of  the  period  by  the  same  method. 
This  arrangement  allows  the  operator  to  stand  behind  the  subject,  who 
thus  has  no  knowledge  as  to  when  the  period  is  to  begin  and  end.  The 
proper  operation  of  the  apparatus  requires  that  the  valve  should  be 
opened  and  closed  at  the  end  of  a  normal  respiration,  which  is  noted  by 
the  movement  of  a  bit  of  goose-down  affixed  to  the  outlet  of  the  valve. 
This  material  was  not  affectecl  by  the  moisture  of  the  breath,  and,  being 
light,  instantly  showed  the  point  of  change  in  the  current  of  air  at  the 
end  of  an  expiration. 

By-pass. — As  in  other  experiments  made  in  this  Laboratory  on  muscu- 
lar work,1  the  ventilating  air-current  was  carried  to  within  a  few  cen- 
timeters of  the  mouthpiece  by  means  of  a  supplementary  pipe  C 
(fig.  1),  operated  by  a  by-pass  valve  B.  This  by-pass  valve  was 
opened  by  a  hand  lever  a  few  seconds  after  the  beginning  of  an 
experimental  period  and  closed  a  few  seconds  before  the  end  of  the 
period.  This  prevented  any  possible  difficulty  hi  obtaining  sufficient 
ventilation  for  the  subject  and  obviated  an  excessive  dead  space. 

Rate  of  ventilation. — The  rate  of  ventilation  during  all  of  the  walking 
experiments  was  the  maximum  capacity  of  the  blower,  namely,  100 
liters  per  minute,  while  for  the  standing  experiments  a  rate  of  65  liters 
per  minute  was  generally  maintained. 

TESTS  OF  THE  UNIVERSAL  RESPIRATION  APPARATUS. 

Although  the  efficiency  of  the  absorbing  system  of  the  universa 
respiration  apparatus  has  been  thoroughly  and  repeatedly  demon- 
strated, it  seemed  advisable  to  test  this  point  further  before  beginning 
the  research,  since  in  the  walking  experiments  a  ventilating  air-current 
with  a  rate  as  high  as  100  liters  per  minute  was  to  be  used  in  place  of 
the  current  of  30  to  40  liters  per  minute  employed  in  most  of  the 
researches  with  this  apparatus.  If  the  water-absorbers  were  inefficient, 
moisture  would  be  carried  over  to  the  carbon-dioxide  absorbers  and 

•Benedict  and  Murschhauser,  Carnegie  Inst.  Wash.  Pub.  No.  231,  1915,  p.  33. 


26  METABOLISM   DURING   WALKING. 

there  collected;  under  these  circumstances  the  change  in  weight  of 
these  absorbers  would  not  represent  the  amount  of  carbon  dioxide 
expired  by  the  subject,  but  would  give  higher  values.  If,  on  the  other 
hand,  the  air-drier  in  the  soda-lime  train  (i.  e.,  the  Williams  bottle 
following  the  two  carbon-dioxide  absorbers)  were  inefficient,  so  that 
moisture  carried  over  from  the  moist  soda-lime  was  not  wholly 
absorbed  by  the  sulphuric  acid  in  the  Williams  bottle,  the  total  increase 
in  weight  would  be  less  than  the  actual  amount  of  carbon  dioxide 
expired  by  the  subject. 

Efficiency  of  the  water-absorbers. — During  rest  experiments  the  usual 
rate  at  which  the  absorbing  system  is  run  is  not  far  from  30  to  35  liters 
per  minute.  For  testing  the  efficiency  of  the  water-absorbers  for  the 
special  demands  of  this  research,  the  absorbing  system  was  run  at  65 
to  100  liters  per  minute  without  a  subject.  The  gain  in  weight  of  the 
water-absorbers  and  the  loss  in  weight  of  the  moistener  were  then  com- 
pared. If  the  water-absorbers  were  efficient,  their  gam  in  weight  would 
be  equal  to  the  loss  in  weight  of  the  moistener.  One  such  test  showed 
a  difference  after  1  hour  of  0.19  gram.  If,  in  12  minutes  (the  usual 
length  of  a  period),  such  an  amount  of  unabsorbed  water  were  carried 
to  the  soda-lime  containers  and  there  absorbed,  the  error  in  the  deter- 
mination of  the  carbon  dioxide  expired  would  amount  to  1.5  c.  c.  per 
minute.  In  another  series  of  experiments  with  five  periods,  the  first 
Williams  bottle  gamed  116  grams,  while  the  second  gained  only  2 
grams.  In  still  another  test  an  additional  Williams  bottle  was  used. 
The  first  gained  in  weight  165.55  grams,  the  second  4.70  grams,  while 
the  third  lost  0.1  gram  in  a  period  of  3  hours'.  As  it  was  the  practice 
to  remove  the  first  Williams  bottle  each  day  and  advance  the  second 
Williams  bottle  to  first  place,  while  a  freshly  filled  bottle  was  used  for 
the  second  water-absorber,  it  may  be  safely  assumed  that  none  of  the 
moisture  in  the  ventilating  air-current  reached  the  carbon-dioxide 
absorbers.  In  the  usual  rest  experiments,  in  which  the  ventilation  is 
about  30  liters  per  minute,  the  "error"  would  be  negligible  in  all  cases. 

Efficiency  of  the  air-drier. — The  second  point,  viz,  that  the  carbon- 
dioxide  absorbers  lost  no  moisture  that  was  not  recovered  by  the  air- 
drier,  was  tested  by  passing  the  ventilating  air-current  through  the 
soda-lime  containers,  which  were  weighed  separately.  The  moisture 
taken  up  by  the  air  in  passing  through  the  moist  soda-lime  should  then 
be  entirely  removed  hi  the  following  Williams  bottle  or  air-drier.  The 
largest  gain  found  during  any  test  was  equivalent  to  an  error  of  3  c.  c. 
per  minute  in  the  carbon-dioxide  determination,  while  the  average 
error  in  a  series  of  tests  was  but  a  fraction  of  1  c.  c.  per  minute.  It  was 
considered,  therefore,  that  the  absorbers  as  used  in  this  research  were 
efficient,  even  at  the  high  rate  of  ventilation  of  100  liters  per  minute. 
During  the  standing  experiments  the  rate  of  ventilation  was  65  liters 
per  minute,  which  allowed  still  greater  efficiency  hi  the  absorbers. 


METHODS   OF   MEASUREMENT.  27 

Tests  for  tightness. — The  care  used  in  making  all  of  the  various  joints 
in  the  system  air-tight  was  well  worth  the  effort,  for  the  apparatus  was 
surprisingly  free  from  leaks.  At  the  beginning  of  each  day's  experi- 
menting a  preliminary  test  for  tightness  was  always  made,  and  if  the 
pointer  on  the  kymograph-drum  showed  any  variations  within  3  min- 
utes, a  leak  was  sought  for.  During  the  research  further  tests  of 
15  and  20  minutes  were  likewise  made  for  possible  leaks.  Early  in 
the  experiment  these  longer  tests  were  made  daily,  but  later  they  were 
made  but  once  a  week  or  even  once  in  two  weeks. 

Tests  of  air  in  the  system. — Before  beginning  the  experiment  of  the 
day  it  was  the  practice  to  empty  the  bell  of  the  spirometer  and  intro- 
duce 4  or  5  liters  of  oxygen  into  the  system.  The  ventilating  appa- 
ratus was  then  operated  for  a  few  minutes,  the  spirometer  again 
emptied,  and  refilled  with  oxygen.  This  prevented  any  danger  of 
deficiency  in  the  oxygen-content  of  the  air  and  an  accumulation  of 
nitrogen.  Duplicate  analyses  of  the  air  after  the  completion  of  a  series 
of  seven  successive  experimental  periods  with  W.  K.  on  one  day  gave 
results  for  oxygen  of  21.90  and  21.93  per  cent. 

TREADMILL. 

A  detailed  description  of  the  treadmill  was  given  hi  the  report  of  the 
previous  study  in  which  this  apparatus  was  used.1  It  consists  of  an 
endless  leather  belt  which  travels  over  two  broad  wooden  pulleys,  sup- 
ported on  ball  bearings,  at  the  ends  of  a  wooden  frame.  The  mill  is 
actuated  by  a  ^2  h.  p.  electric  motor.  The  belt  between  the  pulleys 
is  supported  by  a  considerable  number  of  steel  tubes,  set  close  together 
but  without  touching  in  a  steel  framework.  Each  tube  is  fitted  at  its 
two  ends  with  annular  steel  ball  bearings.  A  rolling,  frictionless  sur- 
face is  thus  provided  for  the  man  to  walk  upon,  which  is  both  sub- 
stantial and  smooth.  The  speed  of  the  motor  may  be  varied  at  will. 
Some  slight  alterations  were  made  in  the  treadmill  for  this  research, 
but  it  was  essentially  as  used  in  the  previous  study  with  the  subject 
walking.  The  general  arrangement  of  the  apparatus  is  shown  in  the 
frontispiece  and  in  figure  1,  page  19. 

Distance  counters. — The  use  of  the  two  counters  recording  the  num- 
ber of  revolutions  of  the  front  pulley  of  the  treadmill  was  continued  in 
this  research,  except  that  the  "continuous  counter,"  for  recording  the 
total  number  of  revolutions,  was  moved  to  the  rear  of  the  treadmill 
frame  and  operated  by  a  wire  from  the  front  pulley.  This  change  was 
made  so  that  the  counter  might  be  in  view  of  the  operator  standing  at 
the  absorber  table.  The  other  counter,  which  is  shown  in  figure  5, 
and  records  the  number  of  revolutions  of  the  pulley  during  the  experi- 
mental period,  is  known  as  the  "period  counter."  It  is  fastened  to 
the  front  pulley  of  the  treadmill  and  is  operated. by  the  bar  /,  which 

'Benedict  and  Murschhauser,  Carnegie  Inst.  Wash.  Pub.  No.  231,  1915,  p.  34. 


28 


METABOLISM   DURING   WALKING. 


turns  the  valve  connecting  the  subject  with  the  ventilating  circuit. 
When  J  is  thrown  at  the  beginning  of  the  period,  it  forces  the  arm  A 
from  its  position  at  stop  B  over  to  stop  C.  This  changes  the  position 
of  the  bar  D  from  d  to  d\.  In  the  latter  position  the  button  E  strikes 
against  D  with  each  revolution  of  the  pulley,  this  contact  operating 
the  counter  R.  A  measurement  of  the  outside  circumference  of  the 
belt  (4.355  meters)  and  a  series  of  tests  showed  that  one  revolution 
of  the  pulley  was  equivalent  to  1.328  meters.  Hence,  from  the  total 
number  of  revolutions  of  the  pulley  as  recorded  by  the  counter  during 
the  period  and  the  equivalent  of  one  revolution  of  the  pulley  (1.33 
meters),  the  exact  distance  walked  by  the  subject  during  the  period 
could  be  calculated.  By  readings  of  the  "continuous  counter"  at 
the  times  when  the  valve  is  opened  and  closed,  itfis  possible  to  verify 
the  records  of  the  "period  counter,"  so  that  a  check  on  the  record  of  the 
distance  walked  was  obtained. 


FIG.  5. — Detail  of  valve-operating  device  and  period  counter. 

Valve-operating  device. — J,  bar  which,  when  pushed  forward,  forces 
button  L  from  under  bar  K.  The  tension  of  spring  M  then  acts 
through  cord  F,  operating  arm  k  and  valve  D  in  figure  1  (p.  19), 
connecting  subject  with  the  ventilating  circuit.  (See  /,  \k,  D, 
J,  L,  K,  and  M,  fig.  1,  p.  19.) 

Period  counter. — When  the  bar  A  is  against  the  stop  B,  the  pivoted 
brass  bar  D  is  in  position  d.  The  brass  button  E  then  slides 
past  the  bar  D  without  displacing  it.  When  the  valve- 
operating  device  J  is  thrown  forward,  the  bar  A  is  pushed 
against  the  stop  C  and  the  bar  D  comes  into  the  position  dj. 
The  button  E  then  strikes  the  bar  D  on  each  revolution  of  the 
pulley  and  the  displacement  of  D  operates  the  counter  R,  giving 
a  record  of  the  number  of  revolutions  of  the  front  pulley  during 
the  experimental  period.  (See  also  fig.  1,  p.  19.) 

Control  of  the  speed  of  walking. — By  means  of  a  stop-watch  the  time 
necessary  for  10  revolutions  of  the  front  pulley  as  shown  by  the  coun- 
ter was  determined,  and  then,  by  reference  to  a  previously  prepared 
table,  the  speed  of  the  treadmill  could  be  readily  obtained.  The  speed 
was  controlled  largely  by  means  of  the  starting-box,  which  permitted 
moderate  adjustment.  As  the  experiments  progressed,  however,  there 


METHODS   OF   MEASUREMENT.  29 

was  frequently  a  change  in  the  speed  of  the  treadmill.  This  change 
was  gradual  and  could  not  be  easily  detected.  It  often  happened, 
therefore,  that  when  the  speed  was  properly  adjusted  at  the  beginning 
of  the  experiment  it  would  be  found  that  as  tune  passed  the  rates  of 
walking  for  the  different  periods  varied  slightly  from  each  other. 
During  the  walking  experiments  in  which  high  grades  were  employed, 
use  was  made  of  the  brake  Q,  Qi,  bearing  on  a  pulley  fixed  to  the  motor 
shaft,  to  aid  in  securing  satisfactory  speed  adjustments.  (See  fig.  1.) 
Angle  of  ascent. — By  means  of  two  nuts  sunk  in  the  head  of  the  tread- 
mill frame  and  two  long  screws  (see  N,  and  NI,  fig.  1,  p.  19),  it  is 
possible  to  elevate  the  front  end  of  the  treadmill  to  an  angle  of  slightly 
over  45°.  A  spirit-level  (0  in  fig.  1),  fastened  to  the  front  of  the  tread- 
mill, indicates  when  both  sides  have  been  adjusted  equally,  so  that  the 
belt  will  run  smoothly  and  true.  To  determine  the  elevation  of  the 
treadmill,  a  light  wooden  triangular  frame  was  constructed,  which  is 
shown  in  figure  6.  This  was  pivoted  at  A  and  E  and  could  be  adjus  ted 
at  B,  by  means  of  a  slot  and  set-nut.  The  distance  between  A  and  C 
was  exactly  100  cm.  When  used  to  find  the  angle  of  elevation,  this 
frame  was  placed  upon  the  walking  surface  of  the  treadmill,  with  the 
edge  AE  resting  on  the  leather  belt.  It  was  then  adjusted  at  B  until 


FIG.  6. — Framework  used  in 
determining  the  angle  of 
ascent. 


the  surface  AB  was  perfectly  level,  as  shown  by  the  spirit-level  S. 
The  elevation  DC  was  next  measured  and  used  to  find  the  sine  of  the 
angle,  or  the  "slant-height."  Since  AC  is  100  cm.,  the  slant-height 
may  be  readily  expressed  as  per  cent.  Accordingly,  when  the  grade 
is  given  as  10  per  cent,  it  is  meant  that  the  subject  in  walking  a  linear 
distance  of  100  meters  raised  himself  to  a  height  equivalent  to  10  meters. 
It  should  be  borne  in  mind  that  for  the  100  linear  meters  thus  walked, 
the  energy  expended  over  and  above  the  standing  requirements  was 
made  up  of  the  energy  required  (1)  for  the  elevation  of  the  body  and 
(2)  for  transporting  the  body  over  the  horizontal  component.  This 
horizontal  component  was  found  from  the  cosine  of  the  angle.  Thus, 
the  subject,  in  walking  on  a  10  per  cent  grade  at  a  rate  of  100  meters 
per  minute,  walked  a  linear  distance  of  100  meters  and  the  vertical 
component  would  be  10  meters,  while  the  horizontal  component  would 
be  100  X  cosine  5°  44'  30",  or  99.5  meters. 


30 


METABOLISM    DURING   WALKING. 


MEASUREMENT  OF  THE  STEP-LIFT. 

With  each  step  in  walking,  the  body  is  raised  to  a  greater  or  less 
degree  in  a  vertical  direction,  and  this  becomes  an  appreciable  factor 
in  the  amount  of  work  which  is  done.  In  the  previous  research  in  this 
Laboratory  on  the  muscular  work  of  walking,  a  dual  record  of  these 
movements  was  obtained  by  means  of  a  work-adder  wheel,  the  spring 
pointer  introduced  by  Professor  Carl  Tigerstedt,1  and  a  kymograph 
record.  The  same  method  of  measurement  was  used  in  this  research 
(see  fig.  7),  except  that  the  cord  leading  to  the  work-adder  wheel  was 
not  attached  directly  to  the  subject.  Instead,  a  light  wooden  fork  was 
employed,  which  was  2  meters  long  and  pivoted  at  one  end,  while  the 
prongs  were  held  closely  at  the  subject's  shoulders  by  elastic  webbing^ 


Fio.  7. — Step-lift  recorder. 

T,  cord  fastened  to  fork  at  back  of  subject 
(see  fig.  1,  p.  19);  A,  spring  providing 
tension  on  cord  T;  B,  recording  wheel 
revolved  by  the  friction  of  cord  T;  C, 
laminated  spring-steel  pawl  to  prevent 
back-lash ;  D,  pen  for  tracing  record ;  E, 
signal  magnet  and  pointer  for  recording 
time. 


(See  S,  fig.  1,  p.  19.)  The  cord  T  (figs.  1  and  7)  from  the  work-adder 
wheel  was  fastened  to  this  fork  at  a  point  directly  behind  the  subject's 
neck.  Although  this  attachment  was  not  so  near  the  center  of  gravity 
of  the  body  as  it  might  be,  the  results  obtained  with  it  were  very  positive 
and  showed  such  slight  movements  as  shifting  the  weight  of  the  body 
from  one  foot  to  the  other — a  movement  scarcely  noticeable  to  the 
observer — while  it  was  less  affected  by  the  relative  position  of  the 
subject  on  the  treadmill.  The  work-adder  wheel  was  directly  con- 


*C.  Tigerstedt,  Skand.  Archiv  f.  Physiol.,  1913,  30,  p.  299.  See  special  application  of  this 
pointer  under  the  conditions  of  this  research  in  Benedict  and  Murschhauser,  Carnegie  Inst. 
Wash.  Pub.  No.  231,  1915,  p.  39. 


METHODS   OF   MEASUREMENT.  31 

nected  to  the  shaft  of  a  revolution-counter,  and  a  record  of  the  total 
movement  of  the  wheel  was  thus  obtained.  The  total  distance  the 
body  was  raised  would  theoretically  be  that  found  by  multiplying  the 
number  of  revolutions  of  the  wheel  by  its  circumference.  These  read- 
ings were  made  for  10  minutes  during  every  period  12  or  13  minutes  in 
length. 

Another  change  in  the  procedure  was  the  use  of  ink  in  place  of 
smoked-paper  tracings  on  the  kymograph  drum.  The  speed  of  the 
kymograph  was  regulated  to  one  complete  revolution  in  3  minutes.  If 
a  lower  speed  than  this  was  used,  the  tracings  of  the  pen  were  frequently 
superimposed  upon  one  another,  making  it  difficult  to  distinguish  the 
individual  steps.  As  it  was  necessary  to  readjust  the  kymograph 
between  the  end  of  each  revolution  and  the  beginning  of  the  next  one, 
only  three  3-minute  tracings  could  be  obtained  during  the  period.  The 
average  of  these  three  3-minute  records  was  taken  as  the  average 
elevation  of  the  body  per  minute  during  the  entire  period  of  12  or  13 
minutes.  The  tracings  upon  the  kymograph-drum  were  used,  how- 
ever, simply  to  check  the  records  of  the  step-lift  counter  in  case  it  failed 
to  act  properly. 

A  criticism1  has  recently  appeared  of  the  method  used  by  Benedict 
and  Murschhauser2  in  measuring  the  step-lift,  to  the  effect  that,  in 
walking,  their  subject  changed  his  position  on  the  treadmill,  thus 
changing  the  length  of  the  cord  from  his  back  to  the  pulley  from  which 
the  cord  ran  to  the  kymograph.  Since  the  criticism  would  apply  to 
some  extent  to  the  method  used  in  this  research  for  measuring  the  step- 
lift,  several  experiments  to  test  this  point  were  made  on  a  subject  not 
used  in  the  research  of  Benedict  and  Murschhauser,  as  neither  of  these 
was  available. 

A  small  incandescent  lamp  was  inclosed  in  a  tin  can  with  a  hole  in  it 
through  which  the  light  would  shine.  One  of  these  lamps  was  fastened 
to  the  back  of  a  subject  at  the  point  of  attachment  used  by  Benedict 
and  Murschhauser  (the  waist-line)  and  a  second  light  to  the  point 
between  the  shoulders  used  in  the  present  research.  For  a  scale  of 
measurement,  two  lights,  1  meter  apart,  were  affixed  to  a  board  centered 
in  the  same  plane  and  behind  the  subject.  Photographs  were  then 
taken  of  the  movements  of  the  spots  of  light  at  the  waist  and  shoulders, 
respectively,  during  the  cycle  of  one  double  step  when  the  subject  was 
walking  on  a  level  and  on  grades  of  approximately  10  and  25  per  cent, 
with  a  speed  in  each  case  of  71  to  74  meters  per  minute.  These  photo- 
graphic records  were  made  not  only  with  the  camera  stationary,  but 
also  with  the  camera  rotated,  so  that  tracings  were  obtained  across  the 
full  length  of  the  photographic  plate. 

By  measuring  the  spacing  of  the  light  spots  on  the  photographic 

'Liljestrand  and  Stenstrom,  Skand.  Arch.  f.  Physiol.,  1920,  39,  p.  167. 
'Benedict  and  Murschhauser,  Carnegie  Inst.  Wash.  Pub.  No.  231,  1915,  p.  39. 


32  METABOLISM   DURING  WALKING. 

plate,  and  the  distance  on  the  1-meter  scale,  it  was  found  that  in  walk- 
ing on  a  level  there  was  an  average  total  forward-and-back  movement 
at  the  waist  of  1.98  cm.,  and  at  the  shoulder  of  0.79  cm.,  corresponding 
to  a  displacement  from  the  vertical  of  0.99  and  0.40  cm.,  respectively, 
while  for  the  10  and  25  per  cent  grades  the  displacement  was  even  less. 
For  a  radius  of  1.5  meters,  which  represents  the  length  of  the  cord  from 
the  shoulders  to  the  pulley,  and  which  connects  the  subject  with  the 
step-lift  counter,  this  displacement  would  amount  to  a  rise  above  the 
horizontal  of  0.01  cm.,  an  amount  too  small  to  be  considered. 

A  comparison  was  also  made  at  this  time  between  the  respective 
readings  of  the  perpendicular  lift,  as  shown  by  the  light  spot  at  the  waist 
(Benedict  and  Murschhauser  method),  and  that  at  the  shoulder 
(H.  M.  S.  method),  and  of  the  kymograph  tracings  taken  simul- 
taneously. On  one  series  of  plates  it  was  found  that,  for  horizontal 
walking,  the  movement  of  the  light  spot  at  the  waist  was  larger  than 
that  at  the  shoulder  by  1  per  cent,  while  the  movement  of  the  shoulder 
light  spot  was  greater  than  that  recorded  by  the  kymograph  by  1.5 
per  cent.  On  another  series  of  plates  it  was  found  that  the  shoulder 
movement  was  slightly  larger  than  the  waist  movement.  In  either 
case  it  may  be  assumed  that  the  variations  agree  within  1  or  2  per  cent 
of  each  other.  In  the  case  of  the  grade  walking  the  differences  were  of 
the  same  order. 

Measurements  were  likewise  made  with  the  subject  walking  up  the 
inclined  treadmill  when  it  was  stationary  and  again  when  it  was 
running.  The  subject  with  the  light  at  the  waist  stepped  from  a  stool 
on  to  the  treadmill  and  walked  to  the  top,  tjhus  giving  an  opportunity 
for  the  measurement  of  the  step-lift  superimposed  on  the  grade-lift. 
The  mill  was  at  an  incline  of  18.4  per  cent.  By  measuring  the  light 
spots  recorded  on  the  plate  when  the  subject  walked  up  the  stationary 
mill,  it  was  computed  that  the  grade  was  14.7  per  cent,  i.  e.,  the  light 
spots  did  not  correctly  show  the  grade  by  —3.7  per  cent.  From  the 
plates  made  when  the  subject  walked  up  the  mill  while  it  was  running, 
the  grade,  computed  from  the  light  spots,  was  19.9  per  cent,  or  1.5  per 
cent  too  high.  Evidently  the  measurements  of  the  step-lift  can  only 
be  regarded  as  approximate. 

The  average  step-lift,  measured  under  these  conditions,  was  5.23  and 
6.48  cm.  per  step,  respectively,  with  the  mill  stationary  and  running. 
Assuming  110  steps  a  minute,  there  was  a  lift  of  approximately  7  meters 
per  minute  when  the  mill  was  running.  From  table  55  (see  p.  214), 
we  find  that  E.  D.  B.  on  December  15,  walking  on  a  15  percent  gradeand 
with  a  speed  of  75  meters  per  minute,  had  an  average  step-lift  of  4.89 
meters  per  minute,  as  measured  by  the  kymograph;  and  on  January  1, 
with  a  20  per  cent  grade  and  a  speed  of  80  meters  per  minute,  it 
was  5.57  meters  per  minute.  If  these  figures  are  increased  by  1.5  per 
cent  to  correspond  with  the  measurements  from  the  photographic 


METHODS   OF   MEASUREMENT.  33 

records,  which  were  that  much  higher  than  the  kymograph  records 
(p.  32),  his  step-lift  per  minute  would  have  been  5.0  and  5.7  meters 
as  compared  with  7  meters  per  minute  for  the  subject  of  this  test. 

Considering  the  difference  in  the  grades  and  speeds,  as  well  as  the 
difference  in  subjects,  and  the  considerable  lapse  of  time  between  the 
results  obtained  in  the  research  and  in  these  later  tests,  there  is  more 
approximation  here  than  might  have  been  expected. 

Step-lift  technique  during  grade  walking. — The  use  of  the  fork  on  the 
shoulders,  as  indicated  in  figure  1,  during  experiments  on  horizontal 
walking,  is,  we  believe,  without  serious  criticism.  After  our  series  of 
experiments  had  been  completed,  the  results  computed  and  tabulated, 
and  an  analysis  of  the  data  was  being  made,  a  criticism  arose  to  the 
effect  that  the  device  pictured  in  figure  1  would  not  record  the  true  step- 
lift,  but  might  include  in  its  registration  a  not  inconsiderable  part  of  the 
grade-lift.  It  appeared  that  the  most  logical  procedure  would  be  to 
place  the  fork  parallel  with  the  belt  of  the  mill  and  to  run  the  cord  from 
the  fork  to  the  first  pulley  in  a  line  at  right  angles  to  the  belt  of  the  mill, 
continue  it  over  the  second  pulley,  and  then  down  to  the  pointer.  It 
was  argued  that  by  this  method  no  movement  in  the  direction  that  the 
belt  was  traveling  could  be  registered,  except  that  of  a  very  long  pendu- 
lum, which,  at  this  arc,  namely,  110  cm.  or  more,  would  be  negligible. 
Consequently,  during  the  preparation  of  this  manuscript  for  publica- 
tion, a  series  of  experiments  was  made  to  test  the  effect  of  this  change 
n  procedure.  Since  the  results  relate  more  particularly  to  the  study  of 
the  step-lift  during  grade  walking,  their  discussion  is  deferred  until  the 
results  of  the  grade-walking  experiments  are  considered.  (See  p.  243.) 

METHOD  OF  STEP-COUNTING. 

For  securing  a  record  of  the  number  of  steps  taken  by  the  subject,  a 
counter  attached  to  the  rear  end  of  the  treadmill  was  connected  with 
the  ankle  of  the  subject  by  means  of  a  long,  weak,  spiral  spring. 
(See  -X",  fig.  1.)  This  spring  had  sufficient  tension  to  operate  the 
counter  when  the  leg  was  thrown  forward,  but  at  the  same  time  put  no 
restriction  upon  the  movements  of  the  subject  as  he  walked.  As  it 
was  not  possible  to  obtain  the  reading  at  the  exact  beginning  of  the 
period,  it  was  the  practice  to  read  the  step-counter  at  the  end  of  the 
first  minute  of  the  period  and  again  at  the  end  of  the  eleventh.  The 
difference  in  the  records,  when  multiplied  by  2,  gave  the  total  number  of 
steps  taken  during  the  10  minutes  of  a  period  12  or  13  minutes  in  length. 

APPARATUS  FOR  DETERMINING  THE  PULSE-RATE. 

Benedict  and  Murschhauser,1  in  their  report  on  the  energy  trans- 
formations in  horizontal  walking,  recorded  a  few  pulse-rates  with  the 

'Benedict  and  Murschhauser,  Carnegie  Inst.  Wash.  Pub.  No.  231,  1915,  pp.  54  and  55. 


34  METABOLISM   DURING   WALKING. 

subject  walking  which  were  taken  by  the  writer  with  a  string  galvano- 
meter. These  were  made  largely  to  test  the  possibilities  of  this  method 
for  determining  the  pulse-rate  during  muscular  work.  While  condi- 
tions did  not  permit  at  that  time  the  collection  of  any  considerable 
amount  of  data,  the  method  was  shown  to  be  practicable.  The  results 
here  reported  were  first  obtained  by  means  of  a  Bock-Thoma  oscillo- 
graph and  later  by  the  use  of  a  Cambridge  string  galvanometer, 
somewhat  modified,  especially  as  to  the  registering  apparatus. 

OSCILLOGRAPH. 

The  Bock-Thoma  oscillograph1  was  equipped  with  four  filaments, 
but  only  one  was  used.  This  was  of  platinum  with  a  diameter  of 
0.0025  mm.  and  a  resistance  of  5,000  ohms.  In  place  of  the  regular 
time  equipment,  a  Jaquet  graphic  chronometer  was  employed,  the 
pointer  of  which  interrupted  a  beam  of  light  in  front  of  the  camera- 
slit.  As  only  the  pulse-rate  was  desired  in  these  experiments,  the 
speed  with  which  the  photographic  paper  was  supplied  to  the  camera 
was  reduced  to  approximately  25  cm.  per  minute.  At  this  speed  each 
pulse-beat  could  be  easily  counted  on  the  record  and  the  distance 
between  the  second  marks  could  be  readily  estimated  to  tenths. 

It  was  found  difficult  at  that  time  to  obtain  photographic  paper  of 
American  manufacture  that  was  sufficiently  sensitive  for  use  with  this 
instrument,  while  the  paper  originally  supplied  with  the  instrument 
was  expensive  and  did  not  keep  well.  Ultimately  a  satisfactory 
European  paper  was  obtained.  The  greatest  difficulty,  however, 
was  found  with  the  filaments  of  the  oscillograph.  These  were  exceed- 
ingly delicate  and  liable  to  damage.  Finally,  when  war  conditions 
made  it  impossible  to  replace  broken  filaments,  the  use  of  the  oscillo- 
graph was  discontinued.  A  typical  record  of  the  pulse-rate  as  ob- 
tained with  this  instrument  is  given  in  C,  figure  8. 

CAMBRIDGE  STRING  GALVANOMETER. 

In  the  fall  of  1916  a  Cambridge  string  galvanometer,  which  had 
previously  been  used  in  the  psychological  work  of  the  Laboratory, 
was  employed  for  measuring  the  pulse-rate  of  the  subjects  in  the  walk- 
ing experiments.  For  this  purpose  a  camera  of  the  so-called  Morse 
type2  was  substituted  for  the  camera  provided  with  the  Cambridge 
instrument.  This  apparatus  was  so  changed  that  the  mechanism 
supplying  the  photographic  paper  to  the  camera  was  driven  by  a 
1/80  h.  p.  motor  of  2,200  r.  p.  m.,  equipped  with  a  rubber  friction 
drive  in  place  of  the  usual  worm  and  gear,  also  with  a  suitable  set  of 
reducing  pulleys.  The  speed  with  which  the  paper  was  being  fed  to 
the  camera  was  indicated  by  a  pointer  fixed  to  the  feed-shaft  revolving 
over  a  graduated  dial.  By  means  of  a  hand  rheostat,  the  speed  of  the 

^roedel,  Theo.  and  Franz,  Deutsch.  Archiv  f.  klin.  Med.,  1912,  109,  p.  52. 
'Manufactured  by  Edelmann  and  Sohn,  Munich,  Germany. 


FIG.  8. — Typical  records  of  pulse-rate  as  obtained  with  oscillograph  and  string  galvanometer. 
A  and  B,  records  with  string  galvanometer:  C,  record  with  oscillograph.     T,  time;  P,  pulse-rate. 


METHODS   OF   MEASUREMENT.  35 

paper  could  be  varied  from  25  to  100  cm.  per  minute.  As  with  the 
oscillograph,  the  rate  of  speed  in  supplying  the  paper  to  the  camera  was 
kept  as  low  as  was  consistent  with  clear  registration,  and  the  time  was 
recorded  by  means  of  a  Jaquet  chronometer.  Typical  records  of  the 
pulse-rate  as  obtained  with  the  Cambridge  string  galvanometer,  with 
the  modifications  noted,  are  given  in  A  and  B  in  figure  8. 

ELECTRODES. 

In  the  beginning  of  the  research  the  subject  was  connected  with  the 
galvanometer  by  means  of  zinc  rods,  wrapped  in  flannel  and  moistened 
with  zinc-chloride  solution.  These  he  carried  in  his  hands.  The 
difference  in  pressure  with  which  the  subject  at  times  gripped  the  elec- 
trodes caused  a  varying  resistance  in  the  system  and  led  to  more  or  less 
difficulty.  Various  other  forms  of  electrodes  were  tried,  but  those 
which  were  most  satisfactory  and  which  were  used  in  practically  the 
whole  study  consisted  of  brass  disks  about  2  cm.  in  diameter,  embedded 
in  kaolin  mixed  to  a  paste  with  dilute  zinc-sulphate  solution.  This 
paste  was  plastered  on  the  chest  just  above  and  below  the  nipples  and 
the  whole  mass  covered  with  a  small  section  of  a  rubber  tennis-ball 
held  in  place  by  strips  of  surgeon's  plaster.  The  rubber  covering 
tended  to  prevent  the  drying  out  of  the  moisture  in  the  paste,  which 
would  change  the  conductivity  of  the  system.  Over  each  rubber 
cover  was  placed  a  pad  of  absorbent  cotton  and  one  or  two  large  elastic 
bandages  to  provide  a  uniform  pressure  upon  the  electrodes. 

The  leather  belt  over  the  pulleys  of  the  treadmill  developed  con- 
siderable static  electricity.  Furthermore,  leakage  from  the  220-volt 
system  used  in  driving  the  treadmill  caused  considerable  difficulty  and 
was  a  constant  source  of  danger  to  the  delicate  string  of  the  galvanome- 
ter. At  first,  use  was  made  of  the  method  employed  by  Benedict  and 
Murschhauser1  of  grounding  the  treadmill  by  means  of  small  sections 
of  brass  chain  trailing  over  the  surface  of  the  leather  belt,  the  chains 
being  connected  to  a  rod  and  attached  to  a  water-pipe  in  the  laboratory. 
Later  the  use  of  the  brass  chain  was  discontinued  and  it  was  replaced 
by  a  roll  of  fine  brass  gauze  which  bore  upon  the  full  width  of  the 
leather  belt.  (See  W  and  TFi,  fig.  1,  p.  19.)  Under  thjese  conditions 
it  was  possible  to  obtain  a  record  of  the  pulse-rate  with  the  subject 
walking  and  wearing  rubber-soled  shoes.  As  at  times  difficulties 
would  develop  unexpectedly,  this  method  was  also  abandoned,  and 
instead  of  grounding  the  treadmill,  it  was  arranged  to  ground  the 
subject.  This  was  done  by  a  third  electrode  similar  to  those  already 
described,  which  was  placed  upon  the  abdominal  wall  and  connected 
to  a  water-pipe  in  the  laboratory.  (See  V,  fig.  1,  p.  19.)  The  new 
method  gave  excellent  results  and  enabled  the  subject  to  walk  on  the 
treadmill  with  ordinary  shoes  without  disturbing  the  delicate  string 
of  the  galvanometer. 

Benedict  and  Murschhauser,  Carnegie  Inst.  Wash.  Pub.  No.  231,  1915,  p.  37. 


36  METABOLISM    DURING   WALKING. 

TECHNIQUE  FOR  SECURING  RECORDS  OF  THE  PULSE-RATE. 

The  electrodes  in  the  moist  kaolin  paste  were  put  in  position  as  pre- 
viously described,  one  above  the  right  nipple  and  the  other  somewhat 
lower  down  on  the  left  side,  and  fastened  in  place  by  means  of  adhe- 
sive tape  and  elastic  bandages.  The  grounding  electrode  was  fas- 
tened to  the  body  near  the  umbilicus  in  a  similar  manner.  The  leads 
were  then  tested  for  response  and  for  any  fault  in  the  grounding  of  the 
subject.  At  the  beginning  of  the  period,  a  signal  was  given  to  the 
operator  in  the  galvanometer  room  and  within  a  minute  of  the  begin- 
ning of  the  experimental  period  a  photographic  pulse-record  for  ap- 
proximately 60  seconds  was  made.  In  the  course  of  3  or  5  minutes 
another  record  was  taken,  and  a  third  at  about  the  end  of  the  tenth 
minute.  Thus,  during  a  12-minute  period,  three  records  were  ob- 
tained at  approximately  regular  intervals.  To  obtain  the  pulse-rate 
per  minute,  the  time  and  pulse-rate  were  subsequently  counted  by  two 
assistants  independently  from  these  records  and  the  average  of  the 
three  records  was  taken  as  representative  of  the  pulse-rate  during  the 
period.  If,  in  any  instance,  difficulty  was  experienced  in  counting 
the  records,  or  if  the  two  assistants  failed  to  agree  in  their  counts, 
another  count  was  made  by  a  third  individual.  In  some  cases,  owing 
to  technical  difficulties,  it  was  possible  to  use  only  a  portion  of  the 
record  for  the  final  count. 

DETERMINATION  OF  THE  BODY-TEMPERATURE. 

Records  of  the  body-temperature  were  secured  in  the  rectum  by 
means  of  an  electrical  resistance  thermometer.  The  resistance  coil  em- 
bedded in  Woods  metal1  in  a  pure-silver  tube  was  provided  with  leads  10 
meters  long  connecting  the  thermometer  with  a  d'Arsonval  galvano- 
meter and  Wheatstone  bridge  placed  in  one  corner  of  the  room.  Two 
of  these  rectal  thermometers,  each  having  a  resistance  of  about  12  ohms, 
were  used  during  the  study.  The  apparatus  was  calibrated  at  tempera- 
tures of  from  35°  to  39°  C.  at  intervals  of  0.25°  to  0.5°  by  immersing 
the  thermometer  bulb  in  a  Dewar  flask.  These  temperatures  were  read 
from  a  standard  Richter  mercurial  thermometer,  with  an  accuracy  of 
0.01°  C.  From  the  points  thus  obtained,  curves  were  constructed  from 
which  temperatures  to  0.01°  C.  were  secured.  These  curves  were 
checked  at  frequent  intervals  during  the  course  of  the  study,  to  make 
sure  that  no  change  had  taken  place  in  the  value  of  the  resistance 
thermometers. 

Before  the  experiment  of  the  day  began,  the  thermometer  was  in- 
serted in  the  rectum  of  the  subject  to  a  definite  depth,  with  the  aid 
of  a  slight  coating  of  mucochondrin.  The  leads  were  fastened  to  the 
buttocks  by  means  of  a  small  piece  of  adhesive  tape  to  prevent  any 
displacement  of  the  thermometer  as  the  subject  walked.  They  were 

and  Soderstrom,  Arch.  Intern.  Med.,  1915,  15,  p.  820. 


METHODS   OF   MEASUREMENT.  37 

then  passed  between  the  legs  and  out  through  the  fly  of  the  walking 
suit  worn  by  the  subject.  The  pointer  on  the  dial  of  the  Wheatstone 
bridge  was  placed  upon  the  100  division-mark  of  the  slide-wire  and  a 
balance  obtained  with  the  compensating  leads  by  an  adjustable  resist- 
ance inserted  between  the  galvanometer  and  the  bridge.  The  com- 
pensating leads  were  then  replaced  by  the  leads  in  the  circuit  of  the 
thermometer.  At  first  the  temperature  records  were  secured  at  the 
beginning  and  end  of  the  periods,  but  after  a  few  days  they  were  taken 
oftener,  usually  every  2  minutes,  and  sometimes  every  minute.  Read- 
ings were  also  made  hi  the  intervals  between  the  periods. 

Balances  with  the  compensating  leads  were  made  at  intervals  during 
the  forenoon.  Between  the  periods,  especially  when  the  subject  had 
been  walking,  he  was  allowed  to  sit  on  a  stool  placed  on  the  treadmill  or 
to  stand  erect.  In  either  case  it  became  necessary  for  his  comfort  to 
throw  a  blanket  around  him.  It  was  found  that  if  the  blanket  in- 
closed a  portion  of  the  leads  (ordinary  lamp  cord),  the  balancing  became 
extremely  difficult;  consequently,  care  was  exercised  to  prevent  more 
than  12  to  18  inches  of  the  leads  from  being  inclosed  within  the  folds  of 
the  blanket.  It  was  also  observed  at  times  that  sitting  affected  the 
temperature  reading,  this  being  due,  possibly,  to  a  change  in  position  of 
the  thermometer  within  the  walls  of  the  rectum.  These  conditions 
were  hard  to  avoid,  but  at  all  times  the  greatest  care  possible  was  used 
in  insetting  the  thermometer  to  a  uniform  depth  and  in  balancing  with 
the  compensating  leads  at  frequent  intervals. 

On  a  few  days,  when  W.  K.  was  doing  a  large  amount  of  work,  the 
weather  was  warm  and  an  electric  fan  was  allowed  to  blow  a  current  of 
air  across  his  face  and  shoulders.  Except  in  these  few  experiments,  the 
subjects  walked  hi  the  still  air  of  the  room,  wearing  heavier  or  lighter 
clothing  in  proportion  to  the  amount  of  work  which  they  were  expected 
to  perform.  The  effect  of  a  moving  air-current  on  the  metabolism, 
general  comfort,  and  efficiency  of  an  individual  has  been  emphasized  by 
Hill  in  a  recent  report.1  With  the  few  exceptions  stated  above,  we  made 
no  attempt  to  control  the  body-temperature  of  the  subject,  other  than 
by  keeping  the  room-temperature  at  approximately  20°  C.  and  allowing 
the  use  of  a  blanket  after  the  cessation  of  the  exercise  of  walking. 

DETERMINATION  OF  THE  BLOOD-PRESSURE. 

During  the  last  month  of  the  study,  that  is,  subsequent  to  March  19, 
1916,  some  determinations  were  made  of  the  blood-pressure  of  E.  D.  B. 
as  a  part  of  the  walking  experiments.  Attempts  to  record  the  blood- 
pressure  while  the  subject  was  walking  were  unsuccessful,  on  account  of 
the  movements  of  the  body.  It  was  necessary,  therefore,  to  make  the 
measurements  immediately  after  the  walking  had  ceased.  The 

1Hill,  The  science  of  ventilation  and  open  air  treatment,  part  I,  Special  Report,  Ser.  No.  32, 
Medical  Research  Committee,  London,  1919. 


38  METABOLISM   DURING   WALKING. 

apparatus  used  consisted  of  an  Erlanger  sphygmomanometer,  with 
which  a  permanent  record  was  secured  on  the  kymograph.  Only  the 
systolic  pressure,  however,  was  noted.  To  assist  in  determining  this 
point,  we  also  employed  a  Nicholson  sphygmomanometer,  placing  a 
cuff  on  the  forearm  and  noting  the  first  indication  of  the  pulse  from  the 
movement  of  the  Fedde*  pith-ball.1  The  pressure  was  then  read  on  the 
Erlanger  sphygmomanometer.  This  double  method  of  securing  the 
systolic  pressure  was  found  to  be  more  satisfactory  under  these  special 
conditions  than  the  use  of  a  stethoscope  on  the  brachial  artery  or  placing 
entire  reliance  upon  the  tracing  of  the  pointer  on  the  Erlanger  sphyg- 
momanometer. 

The  cuffs  were  placed  on  the  subject's  right  arm  before  the  experi- 
ment began  and  were  worn  by  him  during  the  entire  forenoon.  In  the 
standing  experiments,  three  determinations  were  made  as  near  to  the 
second,  sixth,  and  tenth  minutes  of  each  period  as  possible.  In  the 
walking  experiments,  the  pressure  was  applied  towards  the  end  of  the 
usual  preliminary  walk.  When  all  was  in  readiness,  the  treadmill  was 
stopped  and  two  determinations  of  the  systolic  pressure  were  made  as 
quickly  as  possible.  The  walking  then  began  again  immediately  and 
the  period  commenced  with  but  little  loss  of  time,  usually  not  more 
than  1  or  2  minutes.  At  the  close  of  the  period,  while  the  subject  was 
still  walking,  the  pressure  was  again  applied,  and  as  soon  as  the  tread- 
mill stopped  a  second  series  of  records  was  secured.  The  average  of 
these  two  observations,  namely,  the  records  after  10  minutes  of  pre- 
liminary walking,  and  after  10  or  12  minutes  of  walking  in  the  period 
proper,  are  recorded  as  the  blood-pressure  for  the  walking  period.  It 
should  be  clearly  understood,  however,  that  these  values  were  made 
while  the  subject  was  standing  and  10  to  20  seconds  after  he  had 
stopped  walking. 

ROUTINE  OF  EXPERIMENTS. 

The  approximate  routine  of  an  experimental  period  during  a  walking 
experiment  was  as  follows:  On  the  arrival  of  the  subject  at  the  Labora- 
tory, records  were  made  of  the  last  meal  taken  and  the  hour  it  was 
eaten  to  insure  that  the  subject  was  in  a  post-absorptive  condition. 
The  electrodes  for  the  pulse-record  were  then  adjusted,  and  if  the 
exercise  was  to  be  severe,  a  change  was  generally  made  to  a  walking- 
suit.  The  man  was  then  weighed  with  clothing,  after  which  the  rectal 
thermometer  was  inserted.  When  the  subject  mounted  the  treadmill, 
a  safety  belt  attached  to  the  ceiling  was  buckled  loosely  about  his  waist. 
The  counters  for  recording  the  number  of  steps  and  the  step-lift  were 
connected  and  read,  also  both  of  the  revolution  counters  on  the  tread- 
mill. The  subject  then  began  the  preliminary  walking  period.  During 
this  period  a  certain  amount  of  air  was  withdrawn  from  the  ventilating 

Diggers,  Circulation  in  health  and  disease,  Philadelphia  and  New  York,  1915,  fig.  53,  p.  198. 


METHODS    OF   MEASUREMENT.  39 

system  and  replaced  by  fresh  oxygen,  the  absorbing  bottles  were 
weighed,  and  the  system  was  tested  for  tightness.  Approximately  2 
minutes  before  the  beginning  of  the  walking  period  proper,  the  mouth- 
piece and  nose-clip  were  adjusted.  A  signal  was  sent  to  the  operator 
in  the  room  where  the  pulse-rate  was  measured,  and  in  quick  succession 
readings  were  made  of  the  ventilation  adder,  the  oxygen  meter  and  its 
temperature,  the  barometer,  and  the  respiration  counter,  these  readings 
being  verified  by  a  second  observer.  The  kymograph  on  which  the 
respiration  was  recorded  was  also  started  and  the  pens  were  adjusted. 

The  walking  period  proper  began  when  the  subject  was  connected 
with  the  ventilating  current  of  air  by  the  opening*  of  the  valve  at  the 
end  of  a  normal  expiration  and  coincident  with  the  starting  of  a  stop- 
watch and  the  reading  of  the  "continuous  counter."  Within  the 
next  30  seconds,  the  by-pass  B  (fig.  1,  p.  19)  was  turned,  the  kymo- 
graph was  started,  which  gave  a  record  of  the  height  of  the  steps,  and 
the  step-counter  and  height-counter  were  read  at  1  minute  and  1  min- 
ute and  10  seconds,  respectively.  During  the  period  that  followed,  the 
operators  were  occupied  in  admitting  oxygen,  recording  the  body- 
temperature  and  pulse-rate,  resetting  the  valve-operating  device  in 
reaoliness  for  the  end  of  the  experiment,  adjusting  or  replacing  the 
kymograph-drum  of  the  step-lift  record  every  3  minutes,  and  weighing 
and  testing  the  carbon-dioxide  absorbers  for  the  next  period.  At 
about  9  minutes  after  the  period  began,  the  efficiency  of  the  carbon- 
dioxide  absorbers  was  tested  by  deflecting  a  portion  of  the  air-current 
through  a  solution  of  barium  hydroxide.  At  the  eleventh  minute 
of  the  period  the  step-counter  was  read;  at  11  minutes  and  10  seconds, 
the  step-lift  counter  was  likewise  read  and  a  warning  signal  sent  to  the 
operator  in  the  pulse-record  room.  At  approximately  the  twelfth 
minute,  the  valve  was  turned  at  the  end  of  a  normal  expiration,  a 
simultaneous  reading  of  the  "continuous  counter"  was  made,  and  the 
period  ended.  Readings  of  the  various  counters  were  recorded,  and 
when  the  carbon  dioxide  in  the  system  had  been  completely  absorbed, 
oxygen  was  admitted  to  bring  the  spirometer-bell  to  its  original  level. 
Finally,  records  were  made  of  the  oxygen-meter  and  its  temperature 
and  of  the  barometer. 

Other  periods  followed  with  similar  routine;  between  the  periods  the 
subject  either  sat,  stood,  or  continued  walking.  During  the  interval 
between  the  periods,  if  the  subject  sat  or  stood,  it  was  usually  consid- 
ered advisable  to  throw  a  blanket  over  his  shoulders  and  around  the 
body,  as  previously  described,  for  ordinarily  he  was  warm  and  per- 
spiring freely  after  the  muscular  exercise  of  walking.  Measurements 
were,  as  a  rule,  made  in  four  to  six  periods  during  the  forenoon.  At  the 
end  of  the  morning  the  subject  was  released  from  the  treadmill  and 
weighed  a  second  time.  A  typical  record-sheet  for  one  period  of  a 
walking  experiment,  with  the  necessary  corrections  and  calculations, 
is  given  in  table  2. 


40 


METABOLISM   DURING   WALKING. 


Snfcject,   B.D.B. 


TABLE  2. — Typical  record  of  walking  experiment. 
Bate,  February  2,  1916. 


Grade,  25  p.  ct. 


Last  aaal,  7  p.m.:  Lamb  broth,  roast  beef,  maahed  potatoes,  squash,   three  slices  bread  and 
butter,  apple  pie. 

Body-weight,  with  clothing:  9U5  a.m.  61.53  to;. 
ItOO  p.m.  61.00  leg. 
Average  61. 27' leg. 


Period  I. 


Began  walking,  10:00:00  a.m. 
Period  began,     10:13:20  a.m. 


Air-current  used  -  100  liters  per  minute. 
Duration  of  period,  12  min. 22-3/5  sec. 
or  12.387  min. 


Carbon  dioxide. 


Absorbers 
BB  •••  v 


(End 

< Start 

(Difference 


Absorber  900 
Total  C02 


lister.  Temperature 

End                           654.60  liters  18.0*  C. 

Start                       834.12  liters  17.8*  0. 

Difference               20.48  liters  Av.l7»9*  C. 
Valve  correction      0.09  j.lter 
Corrected  meter      20.57  liters 

Barometer  772.4  mm. 

Correction  for  temperature        2.7  mm. 

769.7  ran. 


900 

Log.  0.5091 
Log.  total  C02 
Log.  volume  COg 


Difference 


5&S  =: 

4.28  gms. 


9.70680  -  10 

1.52757 

1.23417  »  17.15  liters. 


.     Barometer        Barometer  temp. 
772.1  inn.                 21.4*  C. 

Valve  correction. 
Start     +2  nm. 

772.6  mm.                 21.1^  0. 
772.4  am.                 21.3*  C. 

Diff  .     +2  mm. 

"  *>'°9  1U*r' 

Log.  meter  factor 

0.00294 

Log.  reduction  to  0'  C.  Uj&J 

9.97237  -  10 

Correction  for  aqueous 

vapor  at  17.9*  0. 
Corrected  barometer 


15.2  mm. 
754.5  mm. 


Log, reduction  .to  760  mmJ'^¥-J  9.99685  -  10 

Log.  corrected  meter  120.87  liters )  1.31323 

Los.  volume  02  1.23539  =  19.29 


liters 


Besniratory  quotient. 

Log.  volume  C02  1.23417 

Log.  volume     02  1.28539 

Log.  respiratory  quotient  9.94878  -  10 


0.39 


Carbon  dioxide  per  minute. 

Log.  volume  C02  in  o.o.  4.23417 

Log.  time   (12.387  min. )  1.09272, 

Log.  C02  per  min.  in  o.O.  3.14145 

C02  per  min.  1385  o.c. 


Oxygen  per  minute. 

Log.  volume  02  la  o.o.  4.28539 
Log.  time  (12.387  min. )  1.09273 
Log.  02  per  min.  In  c.c.  3.19267 
Og  per  min.  1558  c.c. 


Ventilation. 


Ventilation  adder  wheel. 
Start  0.00 

End  85.75 

Ho.  of  revolutions    83.75  x  4.9  liters  «  410.38  liters, 

Respiration  rate. 
Counter. 


410.38 


12.387  min. 


3S.13  liters  per  min. 
r  80.75  liters  per 
min.   (reduced). 


End  3249 
Start  2974 
Difference  275 


275 


12.387  min. 


22.1  per  min. 


METHODS   OF   MEASUREMENT. 
TABLE  2. — Typical  record  of  walking  experiment  (continued). 

Distance  walked. 


End 

Start 

Revolutions  of  wheel 


Continuous 

counter. 

Period  counter. 

Total  distance  preliminary  to  period, 

Preliminary. 

Period. 

451  x  1.33  •  602  meters. 

21216 

21638 

57037 

20765 

21216 

56614 

Distance  per  minute  in  period. 

lei       451 

V422 

____423, 

422.5  x  1.33         .,  „  

13  per  min. 

42T.5 

J.<*.ob'    nin. 

At  end  of  1  min. 
At  end  of  11  min. 
For  10  min. 


Time. 

9:45  a.m. 

9:55  a.m. 
10:00  a.m. 
10:05  a.m. 
10:13  a.m. 
10:16  a.m. 
10:20  a.m. 
10:23  a.m. 


Time. 

9:56:30  a.m. 
10:13:00  a.m. 
10:15:00  a.m. 
10:18:30  a.m* 
10:23:30  a.m. 


Step— counter. 

Beading. 

91617 

92047 

430  x  2  •  860  steps 
or  86.0  steps  per  min. 


Step-lift 


At  end  of  1  min.  10  sec. 
At  end  of  11  min.  10  sec. 
For  10  min. 


Reading 
64748.5 
64852.9 

104.4  z  0.393  meter 

=  41.0  meters 

or  4.10  meters  per  min. 


Bridge. 
200 
209 

235 
246 
255 


Beats. 
73 

136 

66 

133 


Rectal  temperature  record. 

Temperature. 

36,48'  C. 

36.62*  0. 

37.02*  C. 
37.19*  C. 
37. 35 •  C. 


Remarks. 

Thermometer  inserted. 
Standing. 
Started  walking. 

Period  began. 


Pulse  record. 

Seconds . 
61 

64 
30 
59 


Bate .  Remarks . 

71.8  Standing. 

— —  Period  began. 

127.5  W&llclng. 
132.0  Walking. 
135.3  Walking. 

131.6  average  for  walking. 


SUBJECTS. 

Eight  subjects  were  used  in  this  study  of  the  effect  of  muscular  work 
upon  the  metabolism,  but  the  greater  part  of  the  material  was  collected 
with  two  men,  E.  D.  B.  and  W.  K.  A  general  description  of  these 
subjects  follows.  The  body-surfaces  were  obtained  by  means  of  the 
height-weight  chart  of  the  Du  Boises.1  Experiments  were  made  with 
still  another  subject  (T.  J.  L.),  but  as  he  found  difficulty  in  breathing 
through  the  mouthpiece  and  the  results  obtained  with  him  were  ob- 
viously erroneous,  the  data  have  not  been  included  in  this  report. 

A.  J.  0. — Born  September  1884;  age  30  years;  height  180  cm.;  nude  weight 
69.5  kg.;  body-surface  1.88  sq.  meters.  Had  previously  served  as  subject  in 
experiments  at  the  Nutrition  Laboratory.  No  trade  or  special  training,  but 
was  of  athletic  build  and  with  some  experience  as  a  professional  ball-player. 
Discontinued  experiments  with  him  early  in  the  research,  as  he  was  unreliable 
in  his  engagements. 

H.  R.  R. — Born  March  13,  1896;  age  19  years;  height  185  cm.;  nude  weight 
70  kg.;  body-surface  1.93  sq.  meters.  Student  at  Harvard  University.  Not 
especially  interested  in  sports.  Somewhat  ungainly  in  movements  and  not 
"easy  going"  in  his  walk.  Had  a  tendency  to  stoop  and  was  of  a  nervous 
temperament.  While  he  was  anxious  and  willing  to  cooperate  in  every  way, 
his  duties  at  college  made  it  difficult  to  use  his  services  as  much  as  would  other- 
wise have  been  possible. 


*Du  Boia  and  Du  Bois,  Arch.  Intern.  Med.,  1916,  17,  p.  863. 


42  METABOLISM   DURING   WALKING. 

T.  H.  H. — Born  September  2,  1886;  age  29  years;  height  171  cm.;  nude- 
weight  54.5  kg.;  body-surface  1.63  sq.  meters.  Occupation,  gardener.  An 
Englishman,  but  recently  arrived  in  this  country,  and  without  a  situation. 
Served  as  subject  but  a  few  weeks,  as  he  secured  permanent  work  at  his 
regular  occupation.  Slow  and  awkward  in  movements,  but  showed  a  desire 
to  cooperate  in  the  experiments. 

W.  K. — Born  December  24, 1885;  age  29  years;  height  162  cm.;  nude  weight 
49.2  kg.;  body-surface  1.51  sq.  meters.  No  trade,  but  had  served  as  waiter 
in  a  restaurant.  Satisfactory  and  reliable;  during  a  part  of  the  research  the 
experiments  were  made  with  this  subject  only,  as  it  was  difficult  to  find 
suitable  men.  Stocky,  well-built,  easy  walker,  possessed  a  considerable 
amount  of  grit,  and  fulfilled  each  requirement  to  the  best  of  his  ability. 

E.  D.  B—  Born  October  23, 1892;  age  23  years;  height  173  cm. ;  nude  weight 
57  kg. ;  body-surface  1.68  sq.  meters.1  Quiet  and  phlegmatic.  Had  lived  in  a 
country  town,  and  though  not  athletic,  was  well-built  and  accustomed  to 
walking.  After  a  few  months'  service,  he  suffered  from  a  strained  tendon  in  his 
foot;  his  use  as  a  subject  was  accordingly  discontinued,  until  the  lameness 
disappeared  (January  6  to  30,  1916,  inclusive).  Examined  on  May  2,  1916, 
by  a  physician,  who  reported  that  "the  heart  sounds  were  of  good  quality; 
no  murmurs  heard;  heart  entirely  normal." 

While  E.  D.  B.  was  incapacitated,  the  standing  and  walking  tests 
were  continued  by  using  volunteer  subjects  from  the  Laboratory  staff, 
all  of  whom  had  assisted  in  the  experiments.  These  men  were : 

J.  H.  G. — Born  April  21,  1895;  age  20  years;  height  185  cm.;  nude  weight 
68.0  kg.;  body-surface  1.89  sq.  meters. 

E.  L.  F, — Born  November  27,  1892;  age  23  years;  height  171  cm.;  nude 
weight  70.4  kg.;  body-surface  1.82  sq.  meters. 

H.  M.  S. — Born  August  31, 1868;  age  48  years;  height  180  cm.;  nude  weight 
60.4  kg.;  body-surface  1.78  sq.  meters. 

STATISTICS  OF  EXPERIMENTS. 

The  statistical  data  obtained  in  this  study  appear  in  chronological 
order  for  each  subject  in  tables  3  to  16a.  Metabolism  measurements 
were  made  on  some  225  days  in  all,  with  a  total  of  approximately  1,300 
experimental  periods.  These  experiments  were  all  carried  out  in  the 
forenoon,  with  the  subject  in  the  post-absorptive  condition,  i.  e.,  ap- 
proximately 12  hours  after  the  last  meal.  The  experimental  periods- 
were  usually  about  12  minutes  in  duration,  except  for  the  severer 
grades  of  walking,  when  the  time  was  reduced  to  10  minutes  and,  in  a 
few  instances,  to  8  minutes. 

All  of  the  results  secured  are  given  in  the  tables  and  represent  the 
gross  outlay  in  the  energy  output.  With  the  exception  of  one  day  when 
the  subject  was  psychically  stimulated,  no  figures  were  excluded  from 
the  averages  except  in  case  of  manifest  error.  Such  exclusions  have 
been  indicated  by  inclosing  the  figures  in  parentheses.  The  averages 
for  the  different  days  are  the  averages  of  the  results  obtained  for  the 

*For  additional  data  regarding  surface  area,  see  paper  by  Benedict  (Am.  Journ.  Physiol.,  1916, 
41,  p.  275)  in  which  photograph,  silhouettes,  and  measurements  are  given  of  E.  D.  B.  as  Sub- 
ject 7. 


STATISTICS   OF   EXPERIMENTS. 


43 


periods  on  the  individual  days,  except  in  the  case  of  the  respiratory 
quotient  and  the  heat-output,  these  two  values  being  recalculated 
from  the  average  carbon  dioxide  and  oxygen.  The  total  averages  for 
the  subjects  were  obtained  by  averaging  the  daily  averages  and  not  by 
averaging  the  data  for  the  individual  periods. 

TABLE  3. — Metabolism  of  A.  J.  0.  and  H.  R.  R.,  standing,  in  experiments  without  food. 

(Values  per  minute.) 


Date. 

Average 
respira- 
tion- 
rate. 

Average 
pul- 
monary 
ventila- 
tion 
(reduced). 

Average 
pulse- 
rate. 

Carbon 
dioxide. 

Oxygen. 

Respira- 
tory 
quotient. 

Heat 
(com- 
puted). 

A.  J.  O. 
1915. 
Feb.  15  ... 

20.8 

liters. 
7.4 

c.  c. 
242 

c.  c. 
265 

0  92 

cals. 

22.6 

7.6 

228 

281 

81 

21.3 

7.8 

222 

271 

.82 

Average.  .  . 

21.6 

7.6 

231 

272 

.85 

1.32 

Feb.  24  

20.2 

7.8 

235 

270 

.87 

21.1 

8.3 

226 

269 

84 

20.0 

7.7 

224 

261 

.86 

20.7 

7.9 

227 

265 

.86 

Average  .  .  . 

20.5 

7.9 

228 

266 

86 

1  30 

Feb.  27  

23.3 

8.0 

223 

268 

84 

23.3 

8.0 

215 

276 

.78 

Average  .  .  . 

23.3 

8.0 

219 

272 

.81 

1.31 

Gen.  av.  (3 
days)  .  .  . 

21.8 

7.8 

226 

270 

.84 

1.31 

H.  R.  R. 
1915. 
Mar.  20  

20.5 

12.1 

259 

327 

.80 

21.0 

11.5 

107 

230 

310 

.74 

20.4 

11.6 

109 

234 

322 

.73 

Average  .  .  . 

(20.6) 

(11.7) 

(108) 

(241) 

(320) 

(.75) 

(1.52) 

Apr.  10  

16.6 

8.1 

99 

247 

306 

.81 

14.9 

6.9 

96 

194 

271 

.72 

15.1 

7.1 

95 

212 

270 

.79 

15.4 

7.0 

94 

228 

291 

.79 

15.1 

7.0 

91 

225 

295 

.77 

Average  .  .  . 

15.4 

7.2 

95 

221 

287 

.77 

1.37 

Apr.  17  

15.8 

6.9 

92 

209 

273 

77 

15.6 

6.7 

93 

210 

273 

.77 

15.2 

6.5 

210 

272 

.78 

15.2 

6.6 

88 

214 

276 

.78 

Average  .  .  . 

15.5 

6.7 

91 

211 

274 

.77 

1.31 

Gen.    av.1 
(2  days)  . 

15.5 

7.0 

93 

216 

281 

.77 

1.34 

'For  Apr.  10  and  17,  1915. 


44 


METABOLISM   DURING   WALKING. 


TABLE  4. — Metabolism  of  T.  H.  H.,  standing,  in  experiments  without  food.     (Values  per 

minute.) 


Date. 

Average 
respira- 
tion- 
rate. 

Average 
pul- 
monary 
ventila- 
tion 
(reduced). 

Average 
pulse- 
rate. 

Carbon 
dioxide. 

Oxygen. 

Respira- 
tory 
quotient. 

Heat 
(com- 
puted). 

1915. 
Feb.  25  

12.5 

liters. 
5.2 

c.  c. 

(217) 

c.  c. 
221 

(0.98) 

cals. 

12.9 

5.0 

199 

227 

.88 

Average  .  .  . 

12.7 

5.1 

199 

224 

.89 

1.10 

Mar.  19  

11.3 

6.8 

97 

196 

226 

.87 

13.5 

7.5 

200 

243 

.82 

13.3 

7.3 

103 

189 

242 

.78 

Average  .  .  . 

12.7 

7.2 

100 

195 

237 

.82 

1.14 

Mar.  22  

13.1 

7.2 

87 

201 

224 

.90 

13.0 

7.0 

90 

189 

216 

.88 

13.6 

7.3 

96 

196 

223 

.88 

Average.  .  . 

13.2 

7.2 

91 

195 

221 

.88 

1.08 

Gen.  av.  (3 
days)  .  .  . 

12.9 

6.5 

96 

196 

227 

.86 

1.11 

TABLE  5. — Metabolism  of  W.  K.,  standing,  in  experiments  without  food.     (Values  per 

minute.) 


Date. 

Average 
respira- 
tion- 
rate. 

Average 
pul- 
monary 
ventila- 
tion 
(reduced)  . 

Average 
pulse- 
rate. 

Carbon 
dioxide. 

Oxygen. 

Respira- 
tory 
quotient. 

Heat 
(com- 
puted). 

1915. 
Feb.  26  

21.3 

liters. 
7.0 

c.  c. 
185 

c.  c. 
209 

0.89 

cals. 

23.1 

6.7 

179 

214 

.84 

23.1 

6.1 

176 

214 

.83 

Average.  .  . 

22.5 

6.6 

180 

212 

.85 

1.03 

Mar.  11  

20.3 

5.5 

78 

170 

(281) 

(.61) 

20.9 

5.8 

80 

168 

235 

.72 

22.5 

6.4 

78 

183 

233 

.79 

Average  .  .  . 

21.2 

5.9 

79 

174 

234 

.74 

1.11 

Mar.  12  

27.0 

6.7 

186 

225 

.83 

26.6 

6.7 

192 

208 

.93 

21.1 

7.8 

201 

207 

.98 

Average  .  .  . 

24.9 

7.1 

193 

213 

.91 

1.05 

STATISTICS   OF   EXPERIMENTS. 


45 


TABLE    5. — Metabolism  of   W.  K.,  standing,  in  experiments   without  food.     (Values  per 

minute.)— Continued. 


Date. 

Average 
respira- 
tion- 
rate. 

Average 
pul- 
monary 
ventila- 
tion 
(reduced)  . 

Average 
pulse- 
rate. 

Carbon 
dioxide. 

Oxygen. 

Respira- 
tory 
quotient. 

Heat 
(com- 
puted) . 

1915 
Mar.  13 

22.5 

liters. 
6.3 

c.  c. 

187 

c.  c. 

264 

0  71 

cals. 

24.1 

8  2 

211 

262 

81 

24.5 

7.7 

201 

234 

86 

Average 

23.7 

7.4 

200 

253 

79 

1.21 

Mar.  16 

20.3 

7.2 

81 

182 

203 

90 

18.2 

5.6 

177 

212 

84 

18.6 

5.7 

187 

222 

85 

Average  .  .  . 

19.0 

6.2 

81 

182 

212 

.86 

1.03 

Mar.  17 

17.1 

5.6 

87 

187 

261 

72 

18.1 

5.8 

82 

186 

253 

74 

19.2 

5  6 

77 

196 

(295) 

(  67} 

Average  .  .  . 

18.1 

5.7 

82 

190 

257 

.74 

1.21 

Mar.  18 

18.2 

8.8 

80 

176 

212 

83 

18.2 

9.1 

81 

177 

212 

84 

18.1 

9  0 

84 

179 

213 

85 

Average  .  .  . 

18.2 

9.0 

82 

177 

212 

.83 

1.03 

May  29 

25.1 

7  0 

75 

205 

238 

86 

21.7 

6  3 

73 

194 

235 

83 

21  4 

6  4 

74 

194 

224 

87 

Average  .  .  . 

22.7 

6.6 

74 

198 

232 

.85 

1.13 

June  1  .  . 

20  6 

6  6 

86 

182 

212 

86 

19  1 

6  2 

85 

(266) 

213 

n  251 

18.8 

6.1 

81 

193 

219 

89 

19.3 

6.3 

87 

194 

209 

93 

Average  .  .  . 

19.5 

6.3 

85 

190 

213 

.89 

1.05 

June  2  

20.2 

9.8 

81 

191 

224 

85 

22.8 

10.7 

78 

189 

236 

81 

21.1 

10.2 

181 

233 

78 

Average..  . 

21.4 

10.2 

80 

187 

231 

.81 

1.11 

June  3  

22  0 

10  4 

79 

177 

231 

77 

22.7 

10.7 

78 

189 

237 

80 

22.4 

10  6 

79 

189 

238 

80 

Average  .  .  . 

22.4 

10.6 

79 

185 

235 

.79 

1.13 

June  4  

20  4 

9  6 

177 

218 

82 

19.7 

9.6 

189 

241 

79 

23.6 

10.6 

74 

183 

238 

77 

Average.  .  . 

21.2 

9.9 

74 

183 

232 

.79 

1.11 

46 


METABOLISM   DURING   WALKING. 


TABLE    5. — Metabolism  of  W.  K.,  standing,  in  experiments  without  food.     (Values  per 

minute. )— Continued. 


Date. 

Average 
respira- 
tion- 
rate. 

Average 
pul- 
monary 
ventila- 
tion 
(reduced)  . 

Average 
pulse- 
rate. 

Carbon 
dioxide. 

Oxygen. 

Respira- 
tory 
quotient. 

Heat 
(com- 
puted) . 

1915 

June  5 

20.7 

liters. 
9.5 

c.  c. 
181 

•  c.  c. 
233 

0.78 

cah. 

20.9 

9.9 

201 

250 

.81 

22  0 

10  3 

199 

247 

81 

Average  .  . 

21.2 

9.9 

194 

243 

.80 

1.17 

June  14          .   . 

20.8 

9.6 

78 

182 

224 

.81 

19  8 

9  3 

176 

209 

.85 

18  8 

8  9 

74 

171 

203 

85 

Average  .  .  . 

19.8 

93 

76 

176 

212 

.83 

1.03 

Gen.  av. 
(14  days) 

21.1 

16.5 

79 

186 

228 

.82 

1.10 

'March  18,  and  June  2  to  14,  inclusive,  omitted  from  average. 

TABLE  6. — Metabolism  of  E.  D.  B.,  standing,  in  experiments  without  food.     (Values  per 

minute.) 


Date. 

Average 
respira- 
tion- 
rate. 

Average 
pul- 
monary 
ventila- 
tion 
(reduced)  . 

Average 
pulse- 
rate. 

Carbon 
dioxide. 

Oxygen. 

Respira- 
tory 
quotient. 

Heat 
(com- 
puted). 

1915. 
Oct.  4. 

11.5 

liters. 
8  2 

c.  c. 
204 

c.  c. 
237 

0  86 

cala. 

12.1 

8  3 

212 

266 

80 

13.3 

8.8 

204 

250 

.82 

Average  .  .  . 

12.3 

8.4 

207 

251 

.82 

1.21 

Oct.  6  

13.2 

8  4 

191 

240 

80 

12.9 

8.5 

197 

247 

.80 

13.1 

8.4 

190 

247 

.77 

12.1 

8.3 

201 

250 

80 

12.8 

8.3 

192 

237 

81 

Average  .  .  . 

12.8 

8.4 

194 

244 

.80 

1.17 

Oct.  8  

13.3 

8  3 

190 

239 

80 

13.4 

8.2 

192 

235 

.82 

13.2 

8.2 

191 

252 

.76 

14.7 

8.6 

190 

245 

.78 

13.6 

8.2 

186 

230 

.81 

Average  .  .  . 

13.6 

8.3 

190 

240 

79 

1.15 

Oct.  9  

13.3 

8  2 

189 

254 

74 

14.1 

8.5 

190 

242 

.79 

14.5 

8.7 

190 

253 

75 

Average  .  .  . 

14.0 

8.5 

190 

250 

.76 

1.19 

STATISTICS   OF   EXPERIMENTS. 


47 


TABLE  6. — Metabolism  of  E.  D.  B.,  standing,  in  experiments  without  food.     (Values  per 

minute. ) — Continued. 


Date. 

Average 
respira- 
tion- 
rate. 

Average 
pul- 
monary 
ventila- 
tion 
(reduced) 

Average 
pulse- 
rate. 

Carbon 
dioxide. 

Oxygen. 

Respira- 
tory 
quotient. 

Heat 
(com- 
puted) . 

1915 
Oct.  11  

14  5 

liters. 
8  7 

c.  c. 
199 

c.  c. 
223 

0.90 

cats. 

15  0 

9  2 

206 

241 

.85 

15  2 

9  2 

197 

230 

.86 

Average 

14  9 

9  0 

201 

231 

.87 

1   13 

Oct.  13  

14.4 

8  2 

172 

225 

.76 

14.8 

8  8 

190 

242 

.79 

14  8 

9  0 

191 

238 

.81 

Average 

14  7 

8  7 

184 

235 

78 

1  12 

Oct.  14  

14.2 

9  0 

192 

233 

.82 

14.4 

9  0 

189 

235 

.81 

14  5 

8  9 

185 

234 

.79 

Average.  .  . 

14.4 

9.0 

189 

234 

.81 

1.13 

Oct.  15  

13  9 

8  6 

183 

231 

.79 

15  3 

9  4 

187 

231 

.81 

15.2 

9.2 

181 

228 

.80 

Average 

14.8 

9  1 

184 

230 

.80 

1.10 

Oct.  16 

14  3 

8  7 

187 

222 

.84 

15  9 

9  4 

188 

211 

.89 

15.2 

9.2 

192 

219 

.88 

Average 

15.1 

9  1 

189 

217 

.87 

1  06 

Oct.  18. 

15  0 

9  4 

204 

238 

.86 

15.2 

9.3 

188 

225 

.84 

14.9 

9.2 

196 

224 

.88 

Average 

15  0 

9  3 

196 

229 

.86 

1  12 

Oct.  19  

16.0 

9.3 

190 

235 

.81 

15.5 

9.2 

188 

246 

.77 

15.8 

9  4 

191 

236 

.81 

Average  .  .  . 

15.8 

9.3 

190 

239 

.80 

1.14 

Oct.  20  

16.0 

9.6 

196 

240 

.82 

16.1 

9.4 

186 

222 

.84 

16  5 

10  0 

202 

240 

.84 

Average.  .  . 

16.2 

9.7 

195 

234 

.83 

1.13 

Oct.  21  

15.3 

9.1 

185 

220 

.84 

16.0 

9.6 

194 

232 

.84 

16  2 

9  5 

189 

216 

.88 

Average  .  .  . 

15.8 

9.4 

189 

223 

.85 

1.08 

48 


METABOLISM   DURING   WALKING. 


TABLE  6. — Metabolism  of  E.  D.  B.,  standing,  in  experiments  without  food.     (Values  per 

minute. ) — Continued. 


Date. 

Average 
respira- 
tion- 
rate. 

Average 
pul- 
monary 
ventila- 
tion, 
(reduced)  . 

Average 
pulse- 
rate. 

Carbon 
dioxide. 

Oxygen. 

Respira- 
tory 
quotient. 

Heat 
(com- 
puted). 

1915 
Oct.  22 

16  6 

liters. 
9  7 

c.  c. 
196 

c.  c. 
222 

0.89 

cats. 

15  8 

9  2 

180 

213 

85 

16  0 

9  3 

185 

216 

.86 

16  1 

9  4 

187 

217 

86 

1  06 

Oct.  23  

15.4 

8.8 

177 

218 

.81 

16  0 

9  4 

188 

227 

83 

16  4 

9  6 

187 

221 

85 

Average 

15  9 

9  3 

184 

222 

.83 

1.07 

Oct.  25 

15  7 

9  2 

196 

214 

92 

16  5 

9  7 

194 

213 

92 

16.0 

9.5 

196 

227 

.87 

Average  . 

16.1 

9  5 

195 

218 

.90 

1.07 

Oct.  26  

17  1 

9  5 

189 

217 

.87 

16.1 

9.4 

186 

212 

.88 

16.4 

9.6 

183 

224 

.82 

Average.  . 

16.5 

9  5 

186 

218 

.85 

1.06 

Oct.  27  

15.4 

8.9 

181 

226 

.80 

16.7 

9.4 

181" 

216 

.84 

15.6 

9.2 

182 

224 

.81 

Average  .  .  . 

15.9 

9.2 

181 

222 

.82 

1.07 

Oct.  28  

15.4 

8.8 

182 

215 

.85 

15.6 

9.2 

187 

229 

.82 

15.7 

9.3 

194 

224 

.87 

Average  .  .  . 

15.6 

9.1 

188 

223 

.84 

1.08 

Oct.  29  

15  2 

8  6 

180 

219 

82 

15.8 

9.1 

188 

228 

.83 

15.4 

8.9 

186 

229 

.81 

Average.  .  . 

15.5 

8.9 

185 

225 

82 

1  09 

Nov.  18  

14.4 

6.1 

183 

207 

88 

14.8 

6.3 

182 

206 

.89 

14.6 

6.2 

181 

205 

.88 

Average  .  .  . 

14.6 

6.2 

182 

206 

.88 

1.01 

Nov.  19  

14.2 

6.1 

190 

211 

90 

15.3 

6.3 

177 

208 

.85 

14.7 

6.4 

180 

207 

.87 

Average  .  .  . 

14.7 

6.3 

182 

209 

87 

1.02 

STATISTICS   OF   EXPERIMENTS. 


49 


TABLE  6. — Metabolism  of  E.  D.  B.,  standing,  in  experiments  without  food.     (Values  per 

minute.) — Continued. 


Date. 

Average 
respira- 
tion- 
rate. 

Average 
pul- 
monary 
ventila- 
tion 
(reduced). 

Average 
pulse- 
rate. 

Carbon 
dioxide. 

Oxygen. 

Respira- 
tory 
quotient. 

Heat 
(com- 
puted). 

1915. 
Nov.  27  

15.4 

liters. 
8.9 

c.  c. 
199 

c.  c. 
216 

0.93 

Cain. 

16.1 

9.4 

222 

16.0 

9.4 

208 

224 

.93 

Average  .  .  . 

15.8 

9.2 

204 

221 

.92 

1.09 

Nov.  29  

16.7 

9.3 

82 

188 

219 

.86 

16.8 

9.4 

188 

213 

.89 

16.6 

9.6 

198 

225 

.88 

Average.  .  . 

16.7 

9.4 

82 

191 

219 

.87 

1.07 

Nov.  30  

16.5 

9.4 

74 

195 

218 

.90 

16.1 

9.3 

192 

223 

.86 

16.5 

9.6 

204 

235 

.87 

Average  .  .  . 

16.4 

9.4 

74 

197 

225 

.88 

1.10 

Dec.  21  

14.7 

8.7 

187 

194 

.97 

15.1 

9.1 

58 

193 

212 

.91 

14.6 

8.8 

191 

214 

.90 

Average.  .  . 

14.8 

8.9 

58 

190 

207 

.92 

1.02 

Dec.  22  

12.6 

7.7 

184 

217 

.85 

12.9 

8.2 

195 

219 

.89 

Average.  .  . 

12.8 

8.0 

190 

218 

.87 

1.07 

Dec.  31  

14.6 

8.9 

193 

242 

.80 

15.4 

9.8 

71 

218 

263 

.83 

15  7 

10.3 

78 

222 

265 

.84 

Average  .  .  . 

15.2 

9.7 

75 

211 

257 

.82 

1.24 

1916. 
Jan.  3  

16.0 

9.5 

199 

229 

.87 

15  0 

9.5 

222 

262 

.85 

15.8 

9.5 

209 

258 

.81 

Average  .  .  . 

15.6 

9.5 

210 

250 

.84 

1.21 

Jan.  4  

14.1 

8.8 

198 

236 

.84 

15.1 

9.6 

216 

242 

.89 

15.8 

10.2 

223 

253 

.88 

Average  .  .  . 

15.0 

9.5 

212 

244 

.87 

1.19 

Jan.  5  

14  8 

8  7 

85 

199 

251 

.79 

15.6 

9.4 

80 

210 

249 

.84 

16.2 

9.3 

78 

208 

259 

.80 

Average  .  .  . 

15.5 

9.1 

81 

206 

253 

.81 

1.22 

50 


METABOLISM   DURING  WALKING. 


TABLE  6. — Metabolism  of  E.  D.  B.,  standing,  in  experiments  without  food.    (Values  per 

minute.) — Continued. 


Date. 

Average 
respira- 
tion- 
rate. 

Average 
pul- 
monary 
ventila- 
tion 
(reduced). 

Average 
pulse- 
rate. 

Carbon 
dioxide. 

Oxygen. 

Respira- 
tory 
quotient. 

Heat 
(com- 
puted). 

1916. 
Jan.  31  

15  4 

liters. 
9  0 

95 

c.  c. 
197 

c.  c. 

232 

0  85 

cals. 

14.6 

9.0 

89 

198 

247 

.80 

16.1 

9.5 

88 

194 

244 

80 

Average  .  .  . 

15.4 

9.2 

91 

196 

241 

.81 

1.16 

Feb.  1  

15  5 

9  6 

96 

220 

277 

79 

16.6 

10.0 

95 

221 

267 

.83 

16.9 

10.1 

93 

217 

261 

.83 

Average  .  .  . 

16.3 

9.9 

95 

219 

268 

.82 

1.29 

Feb.  12  

14  4 

8  8 

65 

191 

244 

78 

1  17 

Feb.  14  

14.9 

9  2 

77 

196 

240 

.82 

1.16 

Feb.  15  

16  2 

10  1 

79 

207 

261 

.79 

1.25 

Feb.  16  

15  5 

9  4 

205 

255 

80 

1  22 

Feb.  17  

16  5 

10  0 

85 

210 

267 

79 

1  28 

Feb.  18  

15.7 

9.5 

76 

205 

264 

.78 

1.26 

Feb.  19  

13.3 

8  2 

52 

208 

243 

.86 

1.18 

Feb.  21  

15.7 

10  0 

78 

225 

268 

.84 

1.30 

Feb.  22  

15  7 

10  0 

76 

217 

245 

.89 

1  20 

Feb.  23  

15  8 

9  5 

73 

214 

288 

74 

1  36 

Feb.  24  

15.0 

9.5 

73 

214 

254 

.84 

15.4 

9  8 

76 

216 

255 

.85 

Average  .  .  . 

15.2 

9.7 

75 

215 

255 

.84 

1.24 

Feb.  25  

15.8 

9.4 

71 

208 

238 

.87 

16.1 

9.7 

71 

210 

258 

.81 

Average.  .  . 

16.0 

9.6 

71 

209 

248 

.84 

1.20 

Feb.  26.. 

15  7 

9  1 

67 

212 

244 

.87 

16.5 

9.7 

72 

212 

258 

.82 

Average  .  .  . 

16.1 

9.4 

70 

212 

251 

.84 

1.22 

Feb.  28.. 

14.4 

9.0 

225 

239 

.94 

15.2 

8.9 

68 

206 

238 

.87 

15.6 

9.5 

70 

209 

255 

.82 

Average  .  .  . 

15.1 

9.1 

69 

213 

244 

.87 

1.19 

Feb.  29  

15.0 

9  0 

69 

182 

225 

81 

14.3 

8.4 

66 

183 

229 

.80 

15.1 

9.0 

69 

185 

237 

.78 

Average.  .  . 

14.8 

8.8 

68 

183 

230 

.80 

1.10 

Mar.  1  

14  6 

8  8 

198 

222 

89 

14.5 

9.1 

202 

234 

86 

14.0 

8.7 

197 

238 

83 

Average.  .  . 

14.4 

8.9 

199 

231 

.86 

1.13 

STATISTICS   OF   EXPERIMENTS. 


51 


TABLE  6. — Metabolism  of  E.  D.  B.,  standing,  in  experiments  without  food.     (Values  per 

minute. ) — Continued. 


Date. 

Average 
respira- 
tion- 
rate. 

Average 
pul- 
monary 
ventila- 
tion 
(reduced)  . 

Average 
pulse- 
rate. 

Carbon 
dioxide. 

Oxygen. 

Respira- 
tory 
quotient. 

Heat 
(com- 
puted). 

1916. 
Mar  2 

15  7 

liters. 
9  3 

78 

c.  e. 
202 

c.  c. 
236 

0.86 

cab. 

16  1 

9  4 

78 

192 

239 

.81 

14.9 

9  0 

80 

198 

244 

.81 

15  5 

9  0 

81 

187 

229 

.82 

16.0 

9  2 

82 

185 

15  3 

9  2 

76 

192 

243 

.79 

Average  .  .  . 

15.6 

9.2 

79 

193 

238 

.81 

1.15 

Mar.  3     

15  0 

8  7 

76 

186 

240 

.78 

15  7 

9  3 

74 

194 

244 

.80 

16  1 

9  5 

76 

197 

241 

82 

15  9 

9  3 

71 

191 

246 

78 

15.8 

9  2 

76 

185 

233 

.80 

15  9 

9  2 

73 

186 

241 

.78 

Average  .  .  . 

15.7 

9.2 

74 

190 

241 

.79 

1.15 

Mar.  20  

14.8 

9  4 

80 

219 

276 

.80 

16  0 

9  8 

82 

215 

272 

.79 

16  4 

9  6 

81 

206 

259 

80 

Average  .  .  . 

15.7 

9.6 

81 

213 

269 

.79 

1.29 

Mar.  22  

15  6 

9  0 

83 

201 

248 

.81 

16.5 

9.4 

81 

206 

255 

.81 

16.2 

9.2 

79 

201 

258 

.78 

Average  .  .  . 

16.1 

9.2 

81 

203 

254 

.80 

1.22 

Mar.  23 

16  1 

9  2 

77 

201 

249 

81 

15.9 

9.0 

73 

196 

251 

.78 

16.1 

9.0 

73 

196 

252 

.78 

Average.  .  . 

16.0 

9.1 

74 

198 

251 

.79 

1.20 

Mar.  24 

16  2 

9  1 

77 

216 

242 

89 

16.6 

9.7 

76 

216 

264 

.82 

15.9 

9  1 

74 

200 

256 

.78 

Average  .  .  . 

16.2 

9.3 

76 

211 

254 

.83 

1.23 

Mar.  29  

15.4 

8.9 

79 

201 

255 

.79 

15.9 

9.2 

82 

200 

267 

.75 

16.1 

9.4 

83 

204 

272 

.75 

Average  .  .  . 

15.8 

9.2 

81 

202 

265 

.76 

1.26 

Mar.  30  

16.5 

9.4 

84 

200 

243 

.83 

15.8 

9.1 

83 

198 

251 

.79 

16.5 

9.6 

83 

200 

251 

.80 

Average  .  .  . 

16.3 

9.4 

83 

199 

248 

.80 

1.19 

52 


METABOLISM   DURING  WALKING. 


TABLE  6. — Metabolism  of  E.  D.  B.,  standing,  in  experiments  without  food.     (Values  per 

minute. ) — Continued. 


Date. 

Average 
respira- 
tion- 
rate. 

Average 
pul- 
monary 
ventila- 
tion 
(reduced)  . 

Average 
pulse- 
rate. 

Carbon 
dioxide. 

Oxygen. 

Respira- 
tory 
quotient. 

Heat 
(com- 
puted) . 

1916. 
Mar.  31  

15  9 

liters. 
9  1 

79 

c.  c. 
201 

c.  c. 
242 

0.84 

cals. 

16  5 

9  5 

81 

202 

256 

.79 

16  2 

9  4 

78 

193 

243 

.80 

Average.  .  . 

16.2 

9.3 

79 

199 

247 

.81 

1.19 

Apr.  1  

16  2 

9  0 

82 

199 

238 

.84 

16.4 

9.4 

80 

198 

235 

.85 

16.7 

9.4 

79 

194 

241 

.81 

Average  .  .  . 

16.4 

9.3 

80 

197 

238 

.83 

1.15 

Apr.  3  

15  2 

Q    Q 

77 

212 

248 

86 

15.9 

9.3 

75 

205 

245 

.84 

15  8 

9  3 

76 

201 

247 

.81 

Average..  . 

15.6 

9.3 

76 

206 

247 

.83 

1.19 

Apr.  4  

15  4 

9  2 

84 

200 

237 

84 

15.5 

9  0 

81 

194 

224 

.87 

15.9 

9.3 

85 

195 

239 

.82 

Average..  . 

15.6 

9.2 

83 

196 

233 

.84 

1.13 

Apr.  5  

11  7 

91 

91 

OO9 

247 

82 

15.7 

9.1 

90 

188 

239 

.79 

16.3 

9.3 

90 

194 

250 

.78 

Average  .  .  . 

15.9 

9.2 

90 

195 

245 

.80 

1.18 

Apr.  6  

1  R     1 

9n 

M 

9fi7 

OK7 

70 

15.7 

9.2 

86 

195 

238 

.82 

16.3 

9.4 

83 

196 

237 

.83 

Average.  .  . 

15.7 

9.2 

86 

198 

244 

.81 

1.17 

Apr.  7  

14  8 

8  8 

79 

1  SH 

238 

78 

14.9 

8.9 

79 

200 

246 

.82 

15.4 

9.0 

82 

194 

242 

.80 

Average  .  .  . 

15.0 

8.9 

80 

193 

242 

.80 

1.16 

Apr.  8  

15  3 

94 

CM 

99J. 

oe-i 

ftQ 

15.2 

9.0 

79 

204 

241 

.85 

15.2 

9.0 

79 

195 

240 

.82 

Average..  . 

15.2 

9.1 

80 

208 

244 

.85 

1.19 

Apr.  10  

14  8 

Q    ft 

Qfl 

91J. 

9QQ 

QO 

15.4 

9.3 

82 

216 

237 

.91 

Average.  .  . 

15.1 

9.2 

81 

215 

235 

.91 

1.16 

STATISTICS   OF   EXPERIMENTS. 


53 


TABLE  6. — Metabolism  of  E.  D.  B.,  standing,  in  experiments  without  food.     (Values  per 

minute.) — Continued. 


Date. 

Average 
respira- 
tion- 
rate. 

Average 
pul- 
monary 
ventila- 
tion 
(reduced) 

Average 
pulse- 
rate. 

Carbon 
dioxide. 

Oxygen. 

Respira- 
tory 
quotient. 

Heat 
(com- 
puted). 

1916. 
Apr.  11  

15.1 

liters. 
8.9 

84 

c.  c. 
207 

c.  c. 

228 

0.91 

cals. 

14.8 

8.9 

77 

202 

241 

.84 

15.1 

9.1 

82 

199 

249 

.80 

Average  .  .  . 

15.0 

9.0 

81 

203 

239 

.85 

1.16 

Apr.  12  

15.5 

9  1 

86 

200 

245 

.82 

15.5 

9.0 

86 

191 

246 

.78 

15.6 

9  4 

79 

202 

270 

.75 

Average  .  .  . 

15.5 

9.2 

84 

198 

254 

.78 

1.21 

Apr.  13  

15.8 

9  2 

83 

203 

232 

.88 

15.6 

9.2 

82 

201 

233 

.87 

16.0 

9  6 

80 

211 

252 

.84 

Average  .  .  . 

15.8 

9.3 

82 

205 

239 

.86 

1.17 

Apr.  14  

15.1 

9  0 

80 

218 

246 

.89 

15.4 

8  9 

82 

200 

233 

.86 

15.8 

9  2 

82 

204 

235 

.87 

Average  .  .  . 

15.4 

9.0 

81 

207 

238 

.87 

1.16 

Apr.  15  

15.5 

9  2 

80 

203 

242 

.84 

15.9 

9  3 

81 

201 

235 

.86 

16.0 

9.3 

81 

197 

241 

.82 

Average  .  .  . 

15.8 

9.3 

81 

200 

239 

.84 

1.16 

Gen.    av. 
(71  days) 

15.4 

9.1 

78 

199 

240 

.83 

1.16 

TABLE  6a. — Average  body-temperature  and  blood-pressure  of  E.  D.  B.,  standing,  in  experi- 
ments without  food.     (Values  per  minute.) 


Date. 

Aver- 
age 
body- 
tem- 
pera- 
ture. 

Date. 

Aver- 
age 
body- 
tem- 
pera- 
ture. 

Blood- 
pres- 
sure. 

Date. 

Aver- 
age 
body- 
tem- 
pera- 
ture. 

Blood- 
pres- 
sure. 

1916. 
Jan.  5  

•c. 

36.89 

1916. 
Jan.  31  

°C. 
37.26 

mm. 

1916. 
Feb.  1  

°C. 
37.29 

mm. 

36.94 

37.22 

37.27 

36.89 

37  19 

37.19 

Average  .  .  . 

36.91 

Average  .  .  . 

37.22 



Average  .  .  . 

37.25 

Feb.  12  

36.80 

Feb.  14  

37.10 

54 


METABOLISM   DURING  WALKING. 


TABLE  60. — Average  body-temperature  and  blood-pressure  of  E.  D.  B.,  standing,  in  experi- 
ments without  food.     (Values  per  minute.) — Continued. 


Date. 

Aver- 
age 
aody- 
tem- 
pera- 
ture. 

Date. 

Aver- 
age 
body- 
tem- 
pera- 
ture. 

Blood- 
pres- 
sure. 

Date. 

Aver- 
age 
body- 
tem- 
pera- 
ture. 

Blood- 
pres- 
sure. 

1916. 
Feb.  15  

°C. 
36.94 
36.88 
37.13 
37.21 
36.36 
37.01 
36.94 
37.25 

1916. 
Mar.  20  

°C. 
36.57 
36.62 
36.60 

mm. 
112 
114 
115 

1916. 
Apr.  5  

°C. 
37.00 
36.91 
36.95 

mm. 
119 
118 
117 

Feb.  16  

Average  .  .  . 
Mar.  22     

Average  .  .  . 
Apr.  6 

Feb.  17  

TjVK     IjS 

Feb.  19  

36.60 

114 

36.95 

118 

TToK    91 

Feb.  22  

36.62 
36.96 
37.05 

111 
110 
110 

36.88 
36.83 
36.82 

117 
116 
115 

Feb.  23..  

Average.  .  . 
Mar.  23  

Average.  .  . 
Apr.  7  

•pvv,    04 

36.94 
36.95 

Average  .  .  . 
Feb.  25  

36.88 

110 

36.84 

116 

36.95 

37.11 
37.08 
37.09 

113 
113 
115 

36.62 
36.41 
36.45 

118 
120 
120 

Average  .  .  . 
Mar  24 

Average  .  .  . 
Apr  8 

37.06 
37.07 

Average  .  .  . 
Feb.  26  

37.09 

114 

36.49 

119 

37.07 

37.49 
37.23 
37.27 

117 
121 
121 

36.66 
36.65 
36.69 

122 
127 
126 

36.99 
37.02 

Average  .  .  . 
Mar.  29     .... 

Average  .  .  . 
Apr.  10 

Average  .  .  . 
Feb.  28  

37.01 

37.33 

120 

36.67 

125 

36.67 
36.75 
36.81 

36.84 
36.63 
36.68 

106 
111 
111, 

37.09 
36.99 

121 
120 

Average  .  . 
Feb.  29  

Average  .  .  . 
Mar.  30  

Average  .  .  . 

ATM.  1  1 

37.04 

121 

36.74 

36.72 

109 

36.85 
36.82 
36.84 

118 
116 
119 

36.76 
36.64 
36.69 

37.03 
37.09 
37.08 

111 
115 
113 

Average.  .  . 

Anr  12 

Average  .  . 
Mar.  2  

Average.  . 
Mar  31 

36.84 

118 

36.70 

36.53 
36.59 
36.50 
36.62 
36.62 
36.68 

37.07 

113 

36.99 
36.98 
36.89 

118 
117 
118 

36.64 
36.59 
36.77 

119 
122 
118 

Average  .  . 

A  r.T-       1Q 

Average  .  . 
Mar.  3 

Average  .  . 
Apr  1 

36.95 

118 

36.67 

120 

36.94 
36.91 
36.93 

115 
118 
117 

36.78 
36.75 
36.68 

113 
115 
118 

Average  .  . 
Apr.  14  

36.59 

36.52 
36.59 
36.31 
36.43 
36.36 
36.45 

Average.  . 
Apr.  3  

36.93 

117 

Average.. 

36.74 

36.32 
36.82 
36.89 

115 

116 
117 
115 

36.92 
36.99 
37.01 

116 
115 
118 

Average  .  . 
Apr.  15  

Average.. 
Apr.  4  

36.97 

116 

36.44 

36.68 

36.94 
36.88 
36.68 

116 

110 
114 
115 

36.95 
36.93 
36.98 

116 
119 
119 

Average  .  . 
Gen.  av.  . 

Average.  . 

36.95 

118 

36.83 

113 

'36.89 

2117 

'For  40  days. 


2For  20  days. 


STATISTICS   OF   EXPERIMENTS. 


55 


TABLE  7. — Metabolism  of  J.  H.  G.,  E.  L.  P.,  and  H.  M.  S.,  standing,  in  experiments  without 

food.     (Values  per  minute.) 


Date. 

Average 
respira- 
tion- 
rate. 

Average 
pul- 
monary 
ventila- 
tion 
(reduced). 

Average 
pulse- 
rate. 

Carbon 
dioxide. 

Oxygen. 

Respira- 
tory 
quotient. 

Heat 
(com- 
puted). 

J.  H.  G. 

1916. 
Jan.  18 

13.4 

liters. 
9.5 

113 

c.  c. 
225 

c.  c. 

269 

0.84 

cals. 

16.1 

10.5 

120 

228 

284 

.80 

17.7 

11  5 

243 

310 

.79 

Average  .  .  . 

15.7 

10.5 

117 

232 

288 

.81 

1.39 

Jan.  19 

15.0 

9.3 

208 

271 

.77 

16.2 

10.3 

106 

191 

262 

.73 

16.5 

10.6 

217 

280 

.78 

Average  .  .  . 

15.9 

10.1 

106 

205 

271 

.76 

1.29 

Jan.  20 

16.6 

11.0 

102 

226 

278 

.82 

17.4 

11.4 

226 

267 

.85 

17.5 

11.5 

109 

222 

285 

.78 

Average  .  .  . 

17.2 

11.3 

106 

225 

277 

.81 

1.33 

Gen.  av.  (3 
days)  .  .  . 

16.3 

10.6 

110 

221 

279 

.79 

1.34 

E.  L.  F. 

Jan.  21 

12.8 

9.4 

97 

230 

295 

.78 

16.8 

10.7 

100 

219 

293 

.75 

15.7 

10.4 

93 

217 

264 

.82 

Average  .  .  . 

15.1 

10.2 

97 

222 

284 

.78 

1.36 

Jan.  22 

11.8 

9.8 

241 

269 

.90 

11.8 

9  4 

228 

249 

92 

13.7 

9  6 

216 

253 

86 

. 

12  4 

9  6 

228 

257 

89 

1  26 

Jan.  24. 

18.1 

11.5 

112 

205 

249 

.83 

17.2 

12.0 

119 

220 

250 

.88 

17.3 

12  6 

117 

241 

263 

.92 

Average  .  .  . 

17.5 

12.0 

116 

222 

254 

.87 

1.24 

Gen.  av.  (3 
days)  .  .  . 

15.0 

10.6 

107 

224 

265 

.85 

1.29 

H.  M.  S. 
Jan  25 

17.8 

10.3 

97 

183 

226 

.81 

17.0 

9.9 

97 

179 

248 

.73 

16.6 

9.9 

98 

189 

241 

.79 

Average.  .  . 

17.1 

10.0 

97 

184 

238 

.77 

1.13 

Jan  26 

17.0 

9  9 

86 

182 

242 

.76 

16  4 

9  9 

87 

184 

237 

78 

16.8 

10  1 

86 

186 

224 

.83 

Average..  . 

16.7 

10.0 

86 

184 

234 

.79 

1.12 

Gen.  av.  (2 
days)  .  .  . 

16.9 

10.0 

92 

184 

236 

.78 

1.13 

56 


METABOLISM   DURING  WALKING. 


TABLE  8. — Metabolism  of  A.  J.  0.  and  H.  R.  R.  during  horizontal  walking  in  experiments 
without  food.     (Values  per  minute.) 


Date. 

Dis- 
tance. 

Aver- 
age 
respira- 
tion- 
rate. 

Aver- 
age 
pul- 
monary 
venti- 
lation 
(re- 
duced). 

Aver- 
age 
pulse- 
rate. 

No.  of 

steps. 

Car- 
bon 
di- 
oxide. 

Oxy- 
gen. 

Res- 
pira- 
tory 
quo- 
tient. 

Heat 
(com- 
puted). 

A.  J.  O. 
1915. 
Feb   15 

meters. 
^3   1 

24  2 

liters. 
13.8 

c.  c. 
585 

c.  c. 

672 

0.87 

cals. 
3.28 

Feb  24       

63.1 

23  7 

19.3 

96.9 

627 

758 

.83 

3.67 

63  8 

24  5 

14.9 

96.8 

619 

750 

.83 

3.63 

Average  . 

63  5 

24  1 

17.1 

96.9 

623 

754 

.83 

3.65 

Mar.    2   

63.8 

22  2 

14.5 

98.7 

635 

735 

.87 

3.58 

60  7 

22  5 

14.0 

93.8 

584 

694 

.84 

3.37 

63.6 

25.4 

19.6 



97.9 

598 

665 

.90 

3.27 

Average  .... 

62.7 

23  4 

16.0 

96.8 

606 

698 

.87 

3.41 

Gen.  av.  (3 
days)  .... 

63.1 

23  9 

15.6 

96.9 

605 

708 

.85 

3.45 

H.  R.  R. 
1915. 
Mar.  20  

67.7 

18  1 

16.8 

115 

105.4 

812 

1,017 

.80 

4.88 

64.5 

18.1 

15.6 

126 

102.2 

740 

936 

.79 

4.48 

Average  .... 

66.1 

18.1 

16.2 

121 

103.8 

776 

977 

.80 

4.69 

Mar.  27  

65.8 

17  4 

16.5 

106 

102.8- 

756 

888 

.85 

4.32 

67.2 
67.5 

18.0 
18.3 

16.1 
16.2 

107 
111 

102.6 
102.4 

724 
725 

896 
908 

.81 
.80 

4.31 
4.36 

Average  .... 

66.8 

17.9 

16.3 

108 

102.6 

735 

897 

.82 

4.33 

Apr.    3  

60.9 

15  5 

15.0 

104 

95.2 

694 

837 

.83 

4.05 

60.5 
60.0 

17.8 
18.4 

15.1 
15.7 

110 
113 

95.0 
95.6 

688 
688 

852 
857 

.81 

.81 

4.10 
4.12 

Average  .... 

60.5 

17.2 

15.3 

109 

95.3 

690 

849 

.81 

4.09 

Apr.  10  

61  1 

17  9 

16  0 

101 

99  0 

718 

887 

81 

4  27 

Apr.  17  

60.0 

16  6 

14.0 

98.4 

667 

799 

83 

3.87 

59.9 

16.1 

14.4 

100 

97.8 

664 

.83 

23.87 

Average  

60.0 

16.4 

14.2 

100 

98.1 

666 

799 

.83 

3.87 

Apr.  24  

61  8 

16  6 

14  3 

96 

99  2 

647 

807 

80 

3  87 

60.2 
60.6 
60.1 

17.2 
18.2 
17.7 

14.1 
13.9 
13.9 

97 

97 
96 

95.0 
94.8 
96.0 

629 
616 
620 

781 
785 
796 

.81 
.79 

.80 

3.76 
3.76 
3.82 

Average  .... 

60.7 

17.4 

14.1 

97 

98.3 

628 

792 

.80 

3.80 

Gen.  av.  (6 
days)  .... 

62.5 

17.5 

15.4 

106 

99.5 

702 

867 

.81 

4.17 

1Computed  from  averages  for  Feb.  24  and  Mar.  2. 

'Computed  from  the  carbon  dioxide  for  the  period  and  the  respiratory  quotient  for  the  day. 


STATISTICS   OF   EXPERIMENTS. 


57 


TABLE  9. — Metabolism  of  T.  H.  H.  during  horizontal  walking  in  experiments  without  food 

(Values  per  minute.) 


Date. 

Dis- 
tance. 

Aver- 
age 
respira- 
tion- 
rate. 

Aver- 
age 
pul- 
monary 
venti- 
lation 
(re- 
duced) 

Aver- 
age 
pulse- 
rate. 

No.  of 

steps. 

Car- 
bon 
di- 
oxide. 

Oxy- 
gen. 

Res- 
pira- 
tory 
quo- 
tient. 

Heat 
(com- 
puted). 

1915. 
Feb.  25  

meters. 
63.4 

liters. 
12.6 

100.7 

c.  c. 
518 

c.  c. 

624 

0.83 

cals. 
3.02 

63.7 

15.9 

11.5 

98.3 

546 

602 

.91 

2.98 

63  7 

15.0 

10.5 

97.9 

544 

607 

.90 

2  99 

Average.  .  .  . 

63.6 

15.5 

11.5 

99.0 

536 

611 

.88 

2.99 

Mar.  19  

65  7 

14.9 

12.0 

98 

107.0 

595 

710 

.84 

3.44 

66.7 
67.1 
67.8 

16.8 
16.7 
15.3 

11.7 
11.5 
11.4 

103 
106 
108 

106.4 
106.2 
106.0 

571 
562 
561 

715 
733 
713 

.80 

.77 
.79 

3.43 
3.49 
3.41 

Average  .... 

66.8 

15.9 

11.7 

104 

106.4 

572 

718 

.80 

3.45 

Mar.  22  

67.5 

14.4 

11.0 

97 

106.6 

582 

722 

.81 

3.47 

67.5 

14.6 

11.0 

105.0 

560 

683 

.82 

3  30 

Average  .... 

67.5 

14.5 

11.0 

97 

105.8 

571 

703 

.81 

3.38 

Mar.  24  

67  4 

14  3 

11  2 

104  8 

588 

685 

.86 

3  34 

68  1 

14  4 

11.2 

104  2 

574 

(746) 

(.77) 

*3  22 

67.8 

13.2 

11.0 

88 

103.6 

574 

652 

.88 

3.19 

Average  .... 

67.8 

14.0 

11.1 

88 

104.2 

579 

669 

.87 

3.27 

Mar.  26  

65  9 

15  3 

11  6 

88 

100  8 

613 

671 

92 

3  32 

67.6 
68.2 

14.2 
13.5 

11.0 
10.3 

88 
84 

101.2 
102.0 

572 
555 

(781) 
646 

(.73) 
.86 

^.IS 
3.15 

Average..  .  . 

67.2 

14.3 

11.0 

87 

101.3 

580 

659 

.88 

3.23 

Mar.  30  

65  9 

13  8 

12  0 

102  0 

607 

683 

.89 

3  35 

66  8 

13  4 

12  1 

102.2 

596 

695 

.86 

3  39 

63.5 

14.4 

11.7 

93 

99.8 

560 

675 

.83 

3.27 

Average  .... 

65.4 

13.9 

12.0 

93 

101.3 

588 

684 

.86 

3.33 

Apr.    5  

62  4 

13  2 

11  3 

99 

99  4 

593 

690 

86 

3  36 

62  7 

13  1 

11  1 

101 

100  4 

575 

13  35 

63.2 

13.8 

11.2 

105 

100.8 

577 

709 

.82 

3.42 

Average  .... 

62.8 

13.4 

11.2 

102 

100.2 

582 

700 

.83 

3.39 

Gen.  av.  (7 
days)  .... 

65.9 

14.5 

11.4 

95 

102.6 

573 

678 

.85 

3.30 

Calculated  from  the  carbon  dioxide  for  the  period  and  the  average  respiratory  quotient  for 
the  day. 


58 


METABOLISM   DURING  WALKING. 


TABLE  10. — Metabolism  of  W.  K.  during  horizontal  walking  in  experiments  without  food. 

(Values  per  minute.) 


Date. 

Dis- 
tance. 

Aver- 
age 
respira- 
tion- 
rate. 

Aver- 
age 
pul- 
monary 
venti- 
lation 
(re- 
duced) 

Aver- 
age 
pulse- 
rate. 

No.  of 

steps. 

Car- 
bon 
di- 
oxide. 

Oxy- 
gen. 

Res- 
pira- 
tory 
quo- 
tient. 

Heat 
(com- 
puted). 

1915. 
Feb  18 

meters. 
65.6 

19.2 

liters. 
10.8 

112.6 

c.  c. 
431 

c.  c. 
629 

0.69 

cols. 
2.95 

66  9 

19  9 

10  4 

116  2 

429 

562 

77 

2  68 

66.3 

19.6 

9.9 

114.7 

66  3 

19  6 

10.4 

114.5 

430 

596 

.72 

2  80 

Feb  26 

64.4 

19.9 

9.7 

114.7 

435 

528 

.82 

2.55 

Mar.    4  

64.0 

21.4 

14.8 

115.4 

(649) 

621 

(1.05) 

^.oe 

62.9 

22  1 

13  3 

113.0 

543 

606 

.90 

2  98 

66  0 

21  0 

13  1 

115  2 

561 

625 

90 

3  08 

64.3 

21  5 

13  7 

114.5 

552 

617 

.90 

3  04 

Mar.    5   

65.3 

20.6 

11.9 

115.3 

532 

596 

.90 

2.93 

65.9 

22.7 

11.6 

114.4 

508 

582 

.87 

2.84 

66.2 

23.8 

11.8 

115.2 

505 

593 

.85 

2.88 

Average  .  .  . 

65.8 

22.4 

11.8 

115.0 

515 

590 

.87 

2.88 

Mar.    8 

66.4 

23.2 

12  2 

116.6 

511 

618 

.83 

2.99 

66.6 

26  8 

12  9 

116  0 

498 

590 

.85 

2.87 

66.6 

27  0 

12  2 

115  6 

486 

584 

84 

2  83 

Average  .  . 

66.5 

25.7 

12.4 

116.1 

498 

597 

.83 

2.89 

Mar.    9 

66.0 

24  1 

11   1 

115  6 

533 

615 

.87 

3  01 

62.5 

26.0 

10.7 

108.6 

436 

553 

.80 

2.65 

62.2 

24  2 

10.2 

109.0 

433 

12.57 

58.6 

23.7 

11.2 

107.6 

421 

511 

.82 

2.47 

Average 

62.3 

24  5 

10  8 

110  2 

456 

560 

81 

2.70 

Mar.  12  

60.9 

24.6 

10.8 

111.2 

452 

593 

.76 

2.82 

58.5 

25  0 

10.4 

109.8 

431 

512 

.84 

2.48 

68.2 

22.9 

11.0 

117.6 

491 

565 

.87 

2.76 

Average.  .  .  . 

62.5 

24.2 

10.7 

112.9 

458 

557 

.82 

2.69 

Mar.  13  

65.1 

18.6 

11.0 

114.0 

477 

598 

.80 

2.87 

64.7 

18.7 

10.6 

113.0 

455 

583 

.78 

2.78 

59.4 

19.4 

10.4 

108  0 

437 

606 

72 

2.85 

59.1 

20  1 

11  2 

107  4 

451 

544 

83 

2.63 

Average.  .  .  . 

62.1 

19.2 

10.8 

110.6 

455 

583 

.78 

2.78 

Mar.  16  

59.2 

21.3 

11.1 

74 

109.8 

461 

558 

.83 

2.70 

62.3 
60.9 
60.6 

20.5 
19.4 
23.1 

11.0 
10.4 
10.9 

77 
78 
78 

112.4 
107.2 
103.6 

452 
444 
438 

546 
606 
565 

.83 
.73 

.78 

2.64 
2.86 
2.69 

Average  .... 

60.8 

21.1 

10.9 

77 

108.3 

449 

569 

.79 

2.72 

'Average  respiratory  quotient  for  the  day  used  in  computing  the  heat-output. 
2Carbon  dioxide  for  the  period  and  average  respiratory  quotient  for  the  day  used  in  comput- 
ing the  heat-output. 


STATISTICS   OF   EXPERIMENTS. 


59 


TABLE  10. — Metabolism  of  W.  K.  during  horizontal  walking  in  experiments  without  food 
(Values  per  minute.) — Continued. 


Date. 

Dis- 
tance. 

Aver- 
age 
respira- 
tion- 
rate. 

Aver- 
age 
pul- 
monary 
venti- 
lation 
(re- 
duced). 

Aver- 
age 
pulse- 
rate. 

No.  of 
steps. 

Car- 
bon 
di- 
oxide. 

Oxy- 
gen. 

Res- 
pira- 
tory 
quo- 
tient. 

Heat 
(com- 
puted). 

1915 
Mar  17  

meters. 
67.3 

22.1 

liters. 
11.4 

75 

117.2 

e.  e. 
520 

e.  e. 
614 

0.85 

cals. 
2.99 

67.4 
67.8 
67.5 

24.8 
22.3 
22.8 

11.5 
11.4 
11.3 

73 

77 

116:8 
116.2 
114.6 

502 

487 
493 

564 
572 
565 

.89 
.85 
.87 

2.77 
2.78 
2  76 

Average  .... 

67.5 

23.0 

11.4 

75 

116.2 

501 

579 

.87 

2.83 

Mar  18         

62.5 

21.2 

11.1 

77 

108.0 

492 

569 

.87 

2  78 

58.4 
60.8 
58.8 

20.7 
22.6 
19.7 

10.2 
10.5 
9.9 

74 
77 
78 

100.0 
106.2 
104.2 

443 
448 
432 

537 
532 
526 

.83 
.84 
.82 

2.60 
2.58 
2.54 

Average  .... 

60.1 

21.1 

10.4 

77 

104.6 

454 

541 

.84 

2.62 

Mar.  23   

64.3 

20.5 

12.0 

83 

111.6 

456 

(678) 

(.67) 

J2.82 

66.4 
66  5 

19.4 
19  6 

11.5 
11  3 

84 

113.4 
111  4 

446 
434 

581 
568 

.77 
76 

2.77 
2  70 

Average  

65.7 

19.8 

11.6 

84 

112.1 

445 

575 

.77 

2  74 

Mar.  25     

67.3 

21.9 

12.8 

89 

114.6 

499 

624 

80 

3  00 

67.5 
67.0 

21.3 
20.5 

12.3 
11.8 

92 
95 

113.4 
110.2 

478 
453 

577 
567 

.83 
.80 

2.79 
2.72 

Average  .... 

67.3 

21.2 

12.3 

92 

112.7 

477 

589 

.81 

2.83 

Mar.  29  

63.3 

18.8 

10.2 

94 

109.0 

426 

539 

.79 

2.58 

60.8 
62.8 

17.7 
17.8 

9.8 
9.4 

94 
103 

108.2 
110.6 

406 
412 

539 
533 

.75 

.77 

2.55 
2.54 

Average  .  .  . 

62.  3 

18.1 

9.8 

97 

109.3 

415 

537 

.77 

2.56 

Mar.  31     

64  8 

18  8 

10  2 

85 

108.2 

454 

530 

86 

2  58 

65.8 

10.2 

85 

109.8 

448 

X2.59 

64.8 
64.9 

18.7 
20.1 

10.1 
9.9 

84 
86 

109.6 
107.6 

438 
425 

525 
516 

.84 
.83 

2.55 
2.50 

Average  .  .  . 

65.1 

19.2 

10.1 

85 

108.8 

441 

524 

.84 

2.54 

June  23  

58  2 

21  7 

10  3 

81 

108.0 

411 

472 

.87 

2.31 

57.1 
56.0 

20.5 
20.7 

10.1 
9.9 

72 

72 

106.0 
105.4 

385 
383 

473 
455 

.82 

.84 

2.28 
2.21 

Average  .  .  . 

57.1 

21.0 

10.1 

75 

106.5 

393 

467 

.84 

2.26 

Gen.  av.  (16 
days).  .. 

63.7 

21.3 

11.1 

83 

111.7 

461 

563 

.82 

2.72 

1Carbon  dioxide  for  the  period  and  average  respiratory  quotient  for  the  day  used  in  com- 
puting the  heat-output. 


60 


METABOLISM   DURING   WALKING. 


TABLE  11. — Metabolism  of  E.  D.  B.  during  horizontal  walking  in  experiments  without  food. 

(Values  per  minute.) 


Date. 

Dis- 
tance 

Aver- 
age 
respira 
tion- 
rate. 

Aver- 
age 
pul- 
monarj 
venti- 
lation 
(re- 
duced) 

Aver- 
age 
pulse- 
rate. 

No.  o: 
steps. 

Car- 
bon 
di- 
oxide. 

Oxy- 
gen. 

Res- 
pira- 
tory 
quo- 
tient. 

Heat 
(com- 
puted) . 

1915. 
Oct.  9 

meters 
57.8 

18.0 

liters. 
16.4 

94.2 

c.  c. 
534 

c.  c. 
710 

0  75 

cals. 
3.36 

56  4 

19.6 

16.2 

91.8 

516 

659 

.78 

3.15 

Average 

57  1 

18.8 

16  3 

93.0 

525 

685 

77 

3.26 

Oct.  11  

56.3 

19.5 

17.6 

89.0 

535 

610 

.88 

2.99 

53  7 

20.0 

15.4 

96.8 

484 

625 

.77 

2.98 

Average  . 

55  0 

19  8 

16  5 

92.9 

510 

618 

83 

2.99 

Oct.  13  

55.8 

17.0 

15.1 

87.0 

611 

^80 

2.93 

Oct.  14  

55  3 

19.5 

16.7 

88.4 

462 

585 

.79 

2.80 

54  2 

20  6 

16  9 

88.2 

458 

600 

.76 

2.85 

54.1 

20.2 

16.8 

.    87.8 

467 

612 

.76 

2.91 

Average  .... 

54  5 

20.1 

16.8 

88.1 

462 

599 

.77 

2.85 

Oct.  15  

55  4 

18  6 

16  4 

88  9 

470 

575 

.82 

2.77 

54.3 

17.9 

15.8 

88.1 

458 

593 

.77 

2.83 

53.6 

15.5 

14.8 

89.4 

469 

609 

.77 

2.90 

Average  .... 

54  4 

17.3 

15  7 

88.8 

466 

592 

.79 

2.84 

Oct.  16  

65  2 

16  3 

16  5 

98  0 

539 

600 

.90 

2  95 

64.9 

19.7 

18.0 

97.4 

529 

618 

.86 

3.01 

65.0 

17.6 

16.6 

97.6 

511 

633 

.81 

3.05 

64.9 

19.1 

17.3 

97.4 

517 

624 

.83 

3.02 

Average  .... 

65.0 

18.2 

17.1 

97.6 

524 

619 

.85 

3.01 

Oct.  18  

63  4 

12  2 

11  9 

96  6 

528 

582 

.91 

2  87 

64.5 

15.2 

12.9 

97.2 

538 

615 

.87 

3.01 

64.4 

16.0 

13.0 

94.4 

535 

600 

.89 

2.95 

64.8 

17.0 

13.3 

97.4 

539 

614 

.88 

3.01 

Average  .... 

64.3 

15.1 

12.8 

96.4 

535 

603 

.89 

2.96 

Oct.  19  

64  6 

15  9 

12  7 

97  0 

522 

591 

.88 

2  90 

64.1 

17.7 

13.1 

96.4 

513 

658 

.78 

3.14 

63.9 

18.3 

13.0 

96.4 

499 

617 

.81 

2.97 

64.5 

18.7 

13.2 

96.2 

515 

669 

.77 

3.19 

Average.  .  .  . 

64.3 

17.7 

13.0 

96.5 

512 

634 

.81 

3.05 

Oct.  20  

64.6 

16  7 

13.6 

97.4 

542 

610 

.89 

3.00 

64.4 

17.8 

13.7 

97.0 

537 

647 

.83 

3.13 

64.7 

19.6 

14.1 

97.8 

532 

644 

.83 

3.12 

64.5 

20.3 

13.9 

97.8 

523 

645 

.81 

3.10 

64.7 

20.9 

14.1 

98.2 

530 

642 

.83 

3.11 

Average  .... 

64.6 

19.1 

13.9 

97.6 

533 

638 

.84 

3.09 

1Assumed. 


STATISTICS   OF   EXPERIMENTS. 


61 


TABLE  11. — Metabolism  of  E.  D.  B.  during  horizontal  walking  in  experiments  without  food- 
(Values  per  minute.) — Continued. 


Date. 

Dis- 
tance. 

Aver- 
age 
respira- 
tion 
rate. 

Aver- 
age 
pul- 
monary 
venti- 
lation 
(re- 
duced). 

Aver- 
age 
pulse- 
rate. 

No.  of 
steps. 

Car- 
bon 
di- 
oxide. 

Oxy- 
gen. 

Res- 
pira- 
tory 
quo- 
tient. 

Heat 
(com- 
puted.) 

1915. 
Oct.  21  

meters. 
63.8 

17.8 

liters. 
13.7 

98.4 

c.  c. 
544 

c.  c. 
603 

0.90 

cola. 
2.97 

63.6 

17.6 

13.3 

97.6 

524 

636 

82 

3.07 

63.7 

20.5 

14.3 

97.0 

532 

636 

84 

3  08 

63  8 

20  4 

13  7 

96.8 

529 

645 

82 

3  11 

64  3 

21  4 

13  5 

96.7 

517 

638 

81 

3  07 

Average 

63  8 

19.5 

13.7 

97.3 

529 

632 

84 

3  07 

Oct.  22 

71.6 

18.7 

14.2 

101.0 

543 

642 

85 

3.12 

72.6 

18.1 

14.0 

100.6 

546 

653 

84 

3.17 

72.6 

18.5 

14.0 

99.6 

540 

665 

81 

3.20 

72.4 

18  8 

14  0 

100.7 

547 

667 

82 

3.22 

Average 

72.3 

18.5 

14.1 

100.5 

544 

657 

83 

3.18 

Oct.  23  

71.6 

15.4 

13.5 

101.8 

564 

667 

.84 

3.23 

72  4 

18  3 

14  3 

101  0 

555 

674 

82 

3.25 

72.2 

18.6 

13.9 

100.6 

542 

662 

82 

3.19 

72  6 

19.4 

14.2 

100.8 

544 

675 

81 

3.25 

Average 

72.2 

17.9 

14.0 

101.1 

551 

670 

.82 

3.23 

Oct.  25. 

72  5 

17.6 

14.3 

101.4 

562 

637 

88 

3.12 

72.9 

15  6 

13.5 

101.1 

551 

665 

83 

3.22 

73  0 

18  3 

14  2 

101  4 

546 

670 

81 

3.22 

73.7 

17.9 

14.0 

101.4 

545 

673 

81 

3.24 

73.7 

18.1 

14.0 

101.4 

547 

679 

81 

3.27 

Average  . 

73.2 

17.5 

14.0 

101.4 

550 

665 

.83 

3.22 

Oct.  26  

72.5 

16.4 

13.1 

103.0 

516 

657 

.79 

3.15 

72.2 

17.0 

13.0 

101.8 

510 

671 

.76 

3.19 

73.5 

19.3 

14.0 

102.4 

529 

680 

.78 

3.25 

72.9 

18.4 

13.5 

102.6 

519 

667 

.78 

3.19 

73.2 

18.7 

13.7 

102.2 

521 

677 

.77 

3.23 

Average.  .  .  . 

72.9 

18.0 

13.5 

102.4 

519 

670 

.78 

3.20 

Oct.  27  

76.6 

19.0 

14.4 

104.2 

557 

663 

.84 

3.22 

77.0 

19.0 

14.2 

103.8 

547 

679 

.81 

3.27 

77.3 

18.9 

14.2 

104.4 

553 

687 

.80 

3.30 

78.3 

18.0 

14.0 

104.6 

565 

705 

.80 

3.38 

78.5 

18.0 

14.0 

105.0 

561 

709 

.79 

3.40 

78.6 

18.6 

14.2 

105.0 

571 

717 

.80 

3.44 

Average  .  .  . 

77.7 

18.6 

14.2 

104.5 

559 

693 

.81 

3.34 

Oct.  28  

77.1 

17.5 

14.4 

106.6 

594 

654 

.91 

3.23 

77.8 

17.7 

14.2 

106.6 

576 

677 

.85 

3.29 

77.8 

19.3 

14.6 

105.8 

568 

688 

.83 

3.33 

78.1 

18.8 

14.4 

106.4 

573 

695 

.83 

3.36 

78.2 

17.8 

14.1 

107.2 

566 

682 

.83 

3.30 

Average  .... 

77.8 

18.2 

14.3 

106.5 

575 

679 

.85 

3.30 

62 


METABOLISM   DURING    WALKING. 


TABLE  11. — Metabolism  of  E.  D.  B.  during  horizontal  walking  in  experiments  without  food. 
(Values  per  minute.) — Continued. 


Date. 

Dis- 
tance. 

Aver- 
age 
respira- 
tion 
rate. 

Aver- 
age 
pul- 
monary 
venti- 
lation 
(re- 
duced). 

Aver- 
age 
pulse- 
rate. 

No.  of 

steps. 

Car- 
bon 
di- 
oxide. 

Oxy- 
gen. 

.Res- 
pira- 
tory 
quo- 
tient. 

Heat 
(com- 
puted). 

1915. 
Oct.  29  

meters. 
77.1 

16.8 

liters. 
13.9 

68 

104.4 

c.  c. 
592 

c.  c. 

689 

0.86 

cols. 
3.36 

78.1 
78.3 
78.5 

19.5 
19.3 
20.9 

14.5 
14.5 
15.4 

77 
88 
93 

106.1 
104.4 
104.4 

570 
577 
597 

688 
704 
723 

.83 
.82 
.83 

3.33 
3.40 
3.50 

Average  

78.0 

19.1 

14.6 

82 

104.8 

584 

701 

.83 

3.39 

Oct.  30  

45.2 

16.7 

11.1 

80.0 

429 

496 

.86 

2.42 

43.5 

18.2 

11.4 

81.0 

419 

474 

.88 

2.32 

43.1 

18.5 

11.1 

79.8 

401 

484 

.83 

2.34 

Average.  .  .  . 

43.9 

17.8 

11.2 

80.3 

416 

485 

.86 

2.36 

Nov.    1  

44.9 

17.4 

11.4 

79.2 

434 

471 

.92 

2.33 

44.5 

19.2 

11.5 

80.0 

411 

473 

.87 

2.31 

43.5 

18.0 

11.2 

79.8 

406 

478 

.85 

2.32 

Average  .  .  . 

44.3 

18.2 

11.4 

79.7 

417 

474 

.88 

2.32 

Nov.    2  

43.9 

18.1 

11.1 

80.8 

420 

470 

.89 

2.31 

43.4 

19.2 

11.3 

79.4 

412 

483 

.85 

2.35 

42.3 

18.3 

10.9 

79.4 

403 

473 

.85 

2.30 

Average  .  .  . 

43.2 

18.5 

11.1 

79.9 

412 

475 

.87 

2.32 

Nov.    3  

45.4 

18.6 

11.1 

80.8* 

415 

461 

.90 

2.27 

44.7 

18.6 

11.0 

80.0 

398 

469 

.85 

2.28 

43.4 

19.1 

10.9 

95.2 

403 

455 

.89 

2.23 

Average  .... 

44.5 

18.8 

11.0 

85.3 

405 

462 

.88 

2.26 

Nov.    4  

53.5 

20.3 

12.2 

86.4 

435 

497 

.87 

2.43 

53.2 

21.2 

12.3 

86.4 

431 

502 

.86 

2.45 

53.9 

21.5 

12.8 

86.6 

438 

526 

.83 

2.54 

Average  .... 

53.5 

21.0 

12.4 

86.5 

435 

508 

.86 

2.48 

Nov.    5  

46.9 

19.3 

11.4 

82.2 

422 

473 

.89 

2.32 

46.2 
45.6 

20.2 
20.0 

11.2 
11.5 

63 

68 

81.8 
81.6 

400 
398 

478 
479 

.84 
.83 

2.32 
2.32 

Average  .... 

46.2 

19.8 

11.4 

66 

81.9 

407 

477 

.85 

2.32 

Nov.    6  

46.8 

18.8 

11.1 

63 

82.0 

407 

457 

.89 

2.24 

45.8 
45.0 

19.1 
18.9 

11.0 
10.9 

67 

71 

80.8 
79.6 

405 
402 

458 
462 

.89 

.87 

2.25 
2.26 

Average  .... 

45.9 

18.9 

11.0 

67 

80.8 

405 

459 

.88 

2.25 

Nov.    8  

55.2 

17.2 

11.9 

89  0 

484 

510 

95 

2.54 

56.1 

19.1 

12.3 

88.2 

480 

523 

.92 

2.59 

57.0 

19.8 

12.3 

89.8 

474 

525 

.90 

2.59 

Average  .... 

56.1 

18.7 

12.2 

89  0 

479 

519 

92 

2.57 

STATISTICS   OF   EXPERIMENTS. 


63 


TABLE  11. — Metabolism  of  E.  D.  B.  during  horizontal  walking  in  experiments  without  food. 
(Values  per  minute.) — Continued. 


Date. 

Dis- 
tance. 

Aver- 
age 
respira- 
tion- 
rate. 

Aver- 
age 
pul- 
monary 
venti- 
lation 
(re- 
duced). 

Aver- 
age 
pulse- 
rate. 

No.  of 

steps. 

Car- 
bon 
di- 
oxide. 

Oxy- 
gen. 

Res- 
pira- 
tory 
quo- 
tient. 

Heat 
(com- 
puted). 

1915. 
Nov.    9 

meters. 
54.9 

20.1 

liters. 
12.3 

88.8 

e.  e. 
460 

e.  e. 

486 

0.95 

eals. 
2.42 

54  5 

21.6 

12.5 

87.6 

448 

(520) 

(.86) 

'2.41 

54  6 

21.0 

12.3 

87.6 

452 

498 

.91 

2.46 

54.7 

20.9 

12.4 

88.0 

453 

492 

.92 

2.43 

Nov.  10  

48.4 

19.8 

11.6 

67 

84.2 

418 

460 

.91 

2.27 

47  8 

21.0 

11.8 

85.2 

411 

476 

.86 

2.32 

47  1 

21   1 

12.0 

84.8 

417 

489 

.85 

2.38 

Average  .... 

47.8 

20.6 

11.8 

67 

84.7 

415 

475 

.87 

2.32 

Nov.  11  

67.1 

20.6 

13.6 

73 

99.0 

524 

560 

.94 

2.78 

68  2 

21.9 

18.3 

98.8 

524 

608 

.86 

2.96 

68  4 

20  1 

13.7 

99.2 

516 

603 

.85 

2.93 

Average.,  .  . 

67.9 

20.9 

15.2 

73 

99.0 

521 

590 

.88 

2.89 

Nov.  12  

66.0 

19.8 

13.6 

81 

99.2 

528 

573 

.92 

2.84 

67.7 

20.3 

14.1 

99.4 

523 

593 

.88 

2.91 

67.6 

21.4 

14.3 

98.8 

530 

592 

.90 

2.92 

Average  .... 

67.1 

20.5 

14.0 

81 

99.1 

527 

586 

.90 

2.89 

Nov.  13  

76.1 

19.6 

14.5 

78 

104.2 

584 

608 

.96 

3.04 

76.9 
77  0 

20.8 
23  9 

15.0 
15.2 

84 

103.2 
104.4 

583 
560 

657 
635 

.89 
.88 

3.23 
3.11 

Average  

76.7 

21.4 

14.9 

81 

103.9 

576 

633 

.91 

3.12 

Nov.  15  

76.3 

19.6 

14.4 

87 

103.0 

606 

631 

.96 

3.15 

77  1 

22  2 

14.9 

104.6 

595 

649 

.92 

3.21 

77.5 

21.3 

14.8 

104.4 

581 

645 

.90 

3.18 

Average  .... 

77.0 

21.0 

14.7 

87 

104.0 

594 

642 

.93 

3.18 

Nov.  16  

76.4 

20.3 

14.4 

76 

102.8 

563 

654 

.86 

3.19 

77.0 
77.4 

21.3 
22.9 

14.3 
14.7 

84 
86 

104.2 
104.1 

538 
530 

657 
658 

.82 
.81 

3.17 
3.17 

Average  

76.9 

21.5 

14.5 

82 

103.7 

544 

656 

.83 

3.17 

Nov.  17  

46.2 

20.4 

12.2 

81 

79.0 

404 

470 

.86 

2.29 

45.4 

20.3 

11.8 

79.0 

394 

471 

.84 

2.28 

45.6 

21.2 

12.3 

79.0 

400 

473 

.85 

2.30 

Average  .... 

45.7 

20.6 

12.1 

81 

79.0 

399 

471 

.85 

2.29 

Nov.  18  

55  7 

19  9 

12.3 

90.8 

424 

507 

.84 

2.46 

54.9 

21.0 

12.5 

87.4 

416 

491 

.85 

2.39 

54.6 

21.7 

12.6 

87.4 

423 

511 

.83 

2.47 

54.9 

21.7 

13.0 

88.0 

428 

516 

.83 

2.50 

54.7 

21.8 

13.0 

87.8 

436 

518 

.84 

2.51 

Average  .... 

55.0 

21.2 

12.7 

88.3 

425 

509 

.84 

2.47 

'Computed  from  the  carbon  dioxide  for  the  period  and  the  respiratory  quotient  for  the  day . 


64 


METABOLISM    DURING   WALKING. 


TABLE  11. — Metabolism  of  E.  D.  B.  during  horizontal  walking  in  experiments  without  food. 
(Values  per  minute.) — Continued. 


Date. 

Dis- 
tance. 

Aver- 
age 
respira- 
tion- 
rate. 

Aver- 
age 
pul- 
monary 
venti- 
lation 
(re- 
duced). 

Aver- 
age 
pulse- 
rate. 

No.  of 

steps. 

Car- 
bon 
di- 
oxide. 

Oxy- 
gen. 

Res- 
pira- 
tory 
quo- 
tient. 

Heat 
(com- 
puted.) 

1915. 
Nov.  19  

meters. 
76  5 

19  7 

liters. 
14  2 

104  8 

c.  c. 
532 

c.  c. 
630 

0  85 

cols. 
3  06 

77.7 

22.9 

15.4 

104.3 

549 

672 

.82 

3.24 

77.9 

22.6 

14.7 

103.0 

529 

665 

.80 

3.19 

78.4 

23.2 

14.6 

104.6 

535 

670 

.80 

3.22 

78.9 

23.8 

14.9 

104.0 

546 

676 

.81 

3.25 

Average  

77.9 

22.4 

14.8 

104.1 

538 

663 

.82 

3.20 

Nov.  22  

48  0 

20  0 

12  0 

82  2 

422 

484 

87 

2  37 

47.3 

20.1 

11.8 

80.2 

416 

486 

.86 

2.37 

46.8 

19.6 

11.5 

79.8 

406 

478 

.85 

2.32 

Average  .... 

47.4 

19.9 

11.8 

80.7 

415 

483 

.86 

2.35 

Nov.  23  

55  5 

20  7 

12  2 

66 

89  2 

445 

491 

90 

2  42 

53.9 

21.2 

12.7 

86.2 

432 

491 

.88 

2.41 

54.9 

21.5 

12.5 

87.8 

440 

495 

.89 

2.43 

Average  .... 

54.8 

21.1 

12.5 

66 

87.7 

439 

492 

.89 

2.42 

Nov.  24  

57  7 

21  6 

13  2 

90  4 

460 

490 

94 

2  44 

57.6 

21.8 

13.3 

89.6 

447 

500 

.89 

2.46 

57.1 

21.1 

13.4 

90.0 

445 

502 

.89 

2.47 

Average  .... 

57.5 

21.5 

13.3 

90.0 

451 

497 

.91 

2.45 

Nov.  26  

65.3 

20.2 

11.7 

98  2 

519 

546 

.95 

2  72 

66.2 

19.8 

11.6 

99.2 

527 

559 

.94 

2.78 

66.2 

22.8 

12.4 

97.6 

515 

564 

.91 

2.78 

Average  .... 

65.9 

20.9 

11.9 

98.3 

520 

556 

.93 

2.76 

Dec.    1  

74  9 

19  5 

13  8 

QO 

101   0 

599 

697 

96 

3  13 

76.4 
77.3 

21.0 
21.6 

15.0 
15.0 

87 
87 

104.8 
106.2 

599 
575 

657 
647 

.91 

.89 

3.24 
3.18 

Average  .... 

76.2 

20.7 

14.6 

85 

105.3 

591 

644 

.92 

3.19 

Dec.    2  

71  3 

20  6 

13  5 

70 

1O1    8 

549 

K7Q 

95 

2  8Q 

71.8 
71.8 

21.4 
22.2 

14.1 
13.7 

81 

82 

101.8 
101.8 

539 
522 

596 

585 

.90 

.89 

2.93 

2.87 

Average  .... 

71.6 

21.4 

13.8 

81 

101.8 

537 

587 

.91 

2.90 

Dec.    3  

70  5 

21  3 

13  5 

CO 

1f)Q    O 

550 

KQ7 

92 

2  95 

71.2 
72.1 

22.3 
23.1 

13.5 
14.3 

86 

101.1 
101.3 

532 
526 

605 
609 

.88 
.86 

2.96 
2.97 

Average  .... 

71.3 

22.2 

13.8 

84 

101.9 

536 

604 

.89 

2.96 

Dec.    4  

47  5 

19  3 

11  1 

79  4 

415 

449 

93 

2  23 

46.6 

18.7 

11.0 

79.2 

395 

448 

.88 

2.20 

45.9 

19.2 

12.1 

78.4 

394 

459 

.86 

2.24 

Average  .... 

46.7 

19.1 

11.4 

79.0 

401 

452 

.89 

2.21 

STATISTICS   OF   EXPERIMENTS. 


65 


TABLE  11. — Metabolism  of  E.  D.  B.  during  horizontal  walking  in  experiments  without  food. 
(Values  per  minute.) — Continued. 


Date. 

Dis- 
tance. 

Aver- 
age 
respira- 
tion- 
rate. 

Aver- 
age 
pul- 
monarj 
venti- 
lation 
(re- 
duced) 

Aver- 
age 
pulse- 
rate. 

No.  of 

steps. 

Car- 
bon 
di- 
oxide. 

Oxy- 
gen. 

Res- 
pira- 
tory 
quo- 
tient. 

Heat 
(com- 
puted). 

1915. 
Dec.    6  

meters. 
45.2 

18  0 

liters. 
10  5 

63 

78.8 

c.  c. 
402 

c.  c. 
440 

0  91 

cals. 
2  17 

45.1 
44.7 

18.7 
19.5 

10.2 
10.6 

67 

67 

78.4 
78.2 

383 
384 

450 
441 

.85 
.87 

2.19 
2.16 

Average  .  .  . 

45.0 

18.7 

10.4 

66 

78.5 

390 

444 

.88 

2.18 

Dec.    7  

43.8 

19  1 

10  8 

75 

78  8 

413 

453 

91 

2  24 

43.1 
50.6 

19.9 
20.8 

11.1 
11.8 

79 

81 

77.2 
75.2 

410 
424 

445 

484 

.92 

.88 

2.20 
2.37 

Average  .... 

45.8 

19.9 

11.2 

78 

77.1 

416 

461 

.90 

2.27 

Dec.  13  

66  8 

19  0 

12  6 

71 

98  6 

465 

540 

86 

2  63 

66.6 
66.7 

20.0 
20.6 

13.1 
13.2 

78 
82 

97.8 
96.4 

476 
457 

582 
556 

.82 
.82 

2.81 
2.68 

Average  .... 

66.7 

19.9 

13.0 

77 

97.6 

466 

559 

.83 

2.70 

1916. 
Jan.  31  

62  0 

19  2 

14  8 

92 

99  0 

553 

659 

84 

3  20 

63.5 

20.7 

14.6 

97.0 

533 

672 

.79 

3.22 

63.4 
63.9 

21.5 
21.4 

14.2 
14.2 

105 

94.4 
93.4 

534 
532 

688 
673 

.78 
.79 

3.29 
3.22 

Average  .... 

63.2 

20.7 

14.5 

99 

96.0 

538 

673 

.80 

3.23 

Feb.    1  

62  9 

20  3 

14  9 

94 

93  4 

572 

650 

88 

3  19 

63.2 
64.3 
63.9 

21.6 
22.5 
'  21.5 

13.9 
13.6 
14.2 

97 
97 
99 

94.4 
94.8 
94.0 

518 
492 
521 

642 
614 
646 

.81 
.80 
.81 

3.09 
2.95 
3.11 

Average  .... 

63.6 

21.5 

14.2 

97 

94.2 

526 

638 

.82 

3.08 

Mar.  20  

59  5 

21  2 

18.1 

514 

604 

85 

2  94 

60.7 

22.8 

18.4 

509 

581 

.88 

2.85 

Average  .... 

60.1 

22  0 

18.3 

512 

593 

86 

2.89 

Mar.  22  

74  8 

21  0 

15  3 

80 

566 

689 

82 

3  32 

76  9 

22  1 

15  4 

88 

581 

703 

83 

3  40 

Average  .... 

75.9 

21.6 

15.4 

84 

574 

696 

82 

3  36 

Mar.  29  

57  6 

22  2 

13  5 

86 

477 

604 

79 

2  89 

55.5 

21  9 

13.8 

85 

479 

593 

81 

2  85 

Average  .... 

56.6 

22.1 

13.7 

86 

478 

599 

.80 

2.88 

Mar.  30  

68  5 

18  0 

15  2 

83 

584 

681 

86 

3  32 

63.6 

23.3 

15.8 

82 

532 

622 

85 

3  02 

Average  .... 

66.1 

20  7 

15  5 

83 

558 

651 

86 

3  17 

Mar.  31  

55  2 

21  7 

15  4 

68 

512 

539 

95 

2  69 

52  9 

21  2 

12  8 

77 

507 

552 

92 

2  73 

Average  .... 

54.1 

21.5 

14.1 

73 

510 

546 

93 

2  71 

66 


METABOLISM   DURING  WALKING. 


TABLE  11. — Metabolism  of  E.  D.  B.  during  horizontal  walking  in  experiments  without  food, 
(Values  per  minute.) — Continued. 


Date. 

Dis- 
tance. 

Aver- 
age 
respira 
tion- 
rate. 

Aver- 
age 
pul- 
monary 
venti- 
lation 
(re- 
duced) 

Aver- 
age 
pulse- 
rate. 

No.  of 

steps. 

Car- 
bon 
di- 
.  oxide. 

Oxy- 
gen. 

Res- 
pira- 
tory 
quo- 
tient. 

Heat 
(com- 
puted). 

1916. 
Apr.     1  < 

meters. 
53.4 

21.7 

liters. 
13.5 

71 

c.  c. 

472 

e.  e. 

547 

0.86 

cala. 
2.67 

51.7 

21.1 

12.9 

451 

540 

.83 

2.61 

50  4 

21  3 

12  3 

80 

445 

536 

.83 

2.59 

Average 

51  8 

21.4 

12.9 

76 

456 

541 

.84 

2.62 

Apr.    3 

35  1 

19  3 

11.7 

68 

401 

443 

.90 

2.18 

35  7 

19  8 

11  7 

70 

406 

464 

.87 

2.27 

36.7 

18.8 

11.0 

75 

391 

464 

.84 

2.25 

Average 

35  8 

19.3 

11.5 

71 

399 

457 

.87 

2.23 

Apr.    4 

35  9 

19  4 

11  6 

69 

395 

475 

.83 

2.30 

37.0 

19.0 

11.0 

74 

385 

466 

.83 

2.25 

37.0 

18.9 

10.8 

73 

378 

488 

.78 

2.33 

Average 

36  6 

19.1 

11.1 

72 

386 

476 

.81 

2.29 

Apr.    5  

77.4 

21.4 

19.7 

87 

598 

732 

.82 

3.53 

76.5 

23.1 

15.5 

92 

580 

708 

.82 

3.42 

79.3 

22.7 

15.8 

96 

600 

726 

.83 

3.51 

Average  . 

77  7 

22.4 

17.0 

92 

593 

722 

.82 

3.48 

Apr.  10  

78.7 

22.2 

17.9 

679 

722 

.94 

3.59 

77.1 

24.0 

19.4 

88 

654 

722 

.91 

3.56 

Average.  .  . 

77.9 

23.1 

18.7 

88 

667 

722 

.92 

3.57 

Apr.  11  

95.9 

21.2 

20.1 

91 

799 

914 

.87 

4.47 

92  0 

24  3 

19.7 

99 

743 

845 

.88 

4.14 

89.0 

24.9 

18.9 

104 

707 

845 

.84 

4.10 

Average.  . 

92  3 

23  5 

19  6 

98 

750 

868 

86 

4  24 

Apr.  12  

89.2 

22  9 

18.8 

86 

731 

901 

.81 

4.34 

89  0 

25.1 

18.6 

92 

705 

868 

.81 

4.18 

86.6 

23  3 

17.6 

677 

840 

.81 

4  04 

Average  .... 

88.3 

23.8 

18.3 

89 

704 

870 

.81 

4.19 

Apr.  13  

99  7 

24  4 

20  9 

95 

819 

928 

88 

4  55 

97.7 

23.5 

20.2 

102 

812 

942 

.86 

4.59 

94.9 

26  2 

19.7 

103 

762 

877 

.87 

4  29 

Average  .... 

97.4 

24.7 

20.3 

100 

798 

916 

.87 

4.48 

Gen.  av.  (61 
days)  .... 

62.2 

20.3 

14.0 

81 

93.0 

508 

595 

.85 

2.89 

STATISTICS   OF   EXPERIMENTS. 


67 


TABLE  lie. — Average  body-temperature  and  blood-pressure  of  E.  D.  B.  during  horizontal 
walking  experiments  without  food.     (Values  per  minute.) 


Date. 

Average 
body- 
tempera- 
ture. 

Blood- 
pressure. 

Date. 

Average 
body- 
tempera- 
ture. 

Blood- 
pressure. 

1916. 
Jan.  31  

°C. 
37.03 

mm. 

1916. 
Apr.    3  

°C. 
36.86 

mm. 
124 

37.20 

37.12 

123 

37.34 

37.31 

121 

37  42 

37  10 

123 

Average 

37  25 

36  55 

117 

Feb.    1  

37.05 

36.73 

118 

37.21 

36.84 

118 

V7    OQ 

37.34 

Average  

36.71 

118 

Average  

37.22 

Apr.    5  

37.06 
37  23 

123 

Mar.  20  

36.59 

122 

37.38 

125 

OC     70 

19Q. 

37  22 

125 

4 

O«    AQ 

199. 

Apr    10 

36  95 

129 

Mar.  22  

36.90 

122 

37.09 

129 

V7  nn 

37  02 

129 

A 

Q«    QC 

ton, 

Apr  11 

36  94 

130 

Mar.  29  

36.91 

124 

37.29 

129 

37.00 

125 

37.43 

129 

Average  

36.96 

125 

Average  

37.22 

129 

Mar.  30  

37.13 

119 

Apr.  12      

36.95 

130 

37.17 

117 

37.28 

07   qo 

129 

ion 

37  15 

118 

37  19 

130 

Mar  31 

36  86 

37.14 

127 

Apr.  13  

37.09 

131 

37  46 

Average  

37.00 

126 

37.62 

131 

Apr.    1  

36  80 

124 

Average  

37.39 

131 

37  17 

123 

Gen.  av.        .    ... 

137  07 

*125 

Average  

37  00 

124 

15  days. 


*For  13  days. 


68 


METABOLISM   DURING   WALKING. 


TABLE  12. — Metabolism  of  J.  H.  G.,  E.  L.  F.,  and  H.  M.  S.  during  horizontal  walking  in 
experiments  without  food.     (Values  per  minute.) 


Date. 

Dis- 
tance. 

Aver- 
age 
respira- 
tion- 
rate. 

Av'age 
pul- 
monary 
venti- 
lation 
(re- 
duced) 

Aver- 
age 
pulse- 
rate. 

No.  of 

steps. 

Car- 
bon 
di- 
oxide. 

Oxy- 
gen. 

Res- 
pira- 
tory 
quo- 
tient. 

Heat 
(com- 
puted). 

J.  H.  G. 
1916. 
Jan.  18  

meters. 
55  3 

18  2 

liters. 
13  6 

96 

83.8 

c.  c. 

578 

c.  e. 
743 

0  78 

cats. 
3  55 

55.2 
54.5 

18.4 
17.5 

13.2 
12.6 

98 
98 

90.6 
90.0 

555 
541 

724 
713 

.77 
.76 

3.45 
3.39 

Average  .... 

55.0 

18.0 

13.1 

97 

88.1 

558 

727 

.77 

3.46 

Jan.  19  

55  3 

17  7 

13  7 

89 

88  9 

553 

689 

81 

3  31 

55.1 

19.7 

17.3 

105.2 

538 

721 

.75 

3.42 

53.8 

20.4 

17.9 

108.8 

521 

699 

.75 

3.31 

Average  .... 

54.7 

19.3 

16.3 

89 

101.0 

537 

703 

.76 

3.34 

Jan.  20  

55  9 

18  6 

17  6 

93 

89  7 

576 

686 

84 

3  33 

55.6 
53.5 

19.6 
20.2 

17.6 
17.8 

94 
97 

96.2 
105.4 

545 
550 

698 
678 

.78 
.81 

3.33 
3.26 

Average  .... 
Gen.  av.  (3 
days)  

55.0 
54.9 

19.5 
18.9 

17.7 
15.7 

95 
94 

97.1 
95.4 

557 
551 

687 
706 

.81 

.78 

3.31 
3.37 

E.  L.  F. 
Jan.  21  

52  5 

16  0 

18  0 

87 

90  6 

638 

804 

80 

3  85 

52.3 
52.5 

18.1 
19.4 

13.9 
14.2 

86 
90 

90.4 

89.8 

549 
541 

711 
715 

.77 
.76 

3.39 
3.40 

Average  

52.4 

17.8 

15.4 

88 

90.3 

576 

743 

.78 

3.55 

Jan.  22  

53  6 

7  9 

14  4 

87 

96  6 

"618 

688 

90 

3  39 

52.5 
52.3 

6.2 
6.4 

13.1 
13.1 

92 
93 

93.2 

580 
589 

703 
683 

.83 
.86 

3.40 
3.33 

Average  .... 

52.8 

6.8 

13.5 

91 

94.9 

596 

691 

.86 

3.37 

Jan.  24  

49  6 

5  4 

13  3 

97 

95  9 

552 

681 

81 

3  28 

49.2 

48.4 

5.4 
5.4 

13.7 
13.8 

101 
101 

100.8 
90.4 

541 
538 

675 
666 

.80 
.81 

3.24 
3.21 

Average.  .  .  . 
Gen.  av.  (3 
days)  .... 

49.1 
51.4 

5.4 
10.0 

13.6 
14.2 

100 
93 

95.7 
93.6 

544 
572 

674 
703 

.81 
.81 

3.24 
3.38 

H.  M.  8. 
Jan.  25  

44  6 

16  6 

12.4 

79  2 

476 

626 

76 

2  97 

42.2 
41.6 

17.9 
18.1 

11.9 
11.9 

92 
93 

76.2 
76.0 

449 
429 

584 
594 

.77 
.72 

2.78 
2.79 

Average  .... 

42.8 

17.5 

12.1 

93 

77.1 

451 

601 

.75 

2.85 

Jan.  26  

53.5 

15  4 

12.7 

90  4 

525 

665 

79 

3  18 

52  7 

17  3 

12.7 

77  2 

495 

647 

77 

3  07 

52.3 

19.3 

12.8 

88 

83.2 

479 

644 

.74 

3.04 

Average.  .  .  . 
Gen.  av.  (2  days) 

52.8 
47.8 

17.3 
17.4 

12.7 
12.4 

88 
91 

83.6 
80.4 

500 
476 

652 
627 

.77 
.76 

3.11 

2.98 

STATISTICS   OF   EXPERIMENTS. 


69 


TABLE  13. — Metabolism  of  A.  J.  0.,  and  H.  R.  R.  during  grade  walking  in  experiments 
without  food.     (Values  per  minute.) 


Date. 

Grade. 

Dis- 
tance. 

Aver- 
age 
respi- 
ration- 
rate. 

Aver- 
age 
pul- 
monary 
venti- 
lation 
(re- 
duced). 

Aver- 
age 
pulse- 
rate. 

No.  of 

steps. 

Car- 
bon 
di- 
oxide. 

Oxy- 
gen. 

Res- 
pira- 
tory 
quo- 
tient. 

Heat 
(com- 
puted) . 

A.  J.  O. 
1915. 
Mar.  2 

p.  ct. 

meters. 
61.1 

24.5 

liters. 
17.6 

94.4 

c.  c. 

749 

c.  c. 
871 

0.86 

cols. 
4.25 

68.1 

25.2 

18.0 

102  6 

822 

955 

.86 

4.66 

Average 

3.6 

64.6 

24.9 

17.8 

98.5 

786 

913 

.86 

4.45 

H.  R.  R. 

1915. 
Mar.  27  

66.4 

24.5 

29.5 

147 

105.6 

1,445 

1,672 

.87 

8.17 

66.4 

26.8 

29.5 

105.4 

1,398 

1,687 

.83 

8.16 

66  8 

27.4 

30.3 

105.4 

1,427 

1,730 

.83 

8.35 

66.6 

30.3 

31.8 

104.8 

1,458 

1,727 

.85 

8.40 

Average  .  . 

10.6 

66.6 

27.3 

30.3 

147 

105.3 

1,432 

1,704 

.84 

8.26 

Apr.  3  .... 

61  7 

24.5 

27.7 

143 

97  4 

1,309 

1,532 

.86 

7.47 

61.9 

25.0 

28.1 

98.8 

1,308 

1,553 

.84 

7.53 

61.8 

26.1 

28.7 

99.6 

1,291 

1,578 

.82 

7.61 

62.2 

27.4 

30.5 

102.6 

1,339 

1,634 

.82 

7.88 

Average  .  . 

10.2 

61.9 

25.8 

28.7 

143 

99.6 

1,312 

1,574 

.83 

7.62 

Apr.  24  

63  8 

23.3 

25.9 

130 

100  6 

1,255 

1,502 

.84 

7.28 

64.2 

23.7 

26.1 

143 

100.6 

1,241 

1,553 

.80 

7.46 

64.1 

24.0 

26.3 

144 

102.0 

1,239 

1,532 

.81 

7.37 

Average  .  . 

10.5 

64.0 

23.7 

26.1 

139 

101.1 

1,245 

1,529 

.81 

7.36 

May  1  ... 

71  8 

23  4 

29.8 

132 

108  2 

1,466 

1,667 

.88 

8.17 

72.5 

25.5 

30.8 

136 

108.8 

1,465 

1,705 

.86 

8.31 

73.1 

26.5 

31.8 

142 

108.6 

1,484 

1,741 

.86 

8.49 

73.2 

27.1 

32.6 

151 

109.2 

1,560 

1,830 

.85 

8.90 

73.0 

27.9 

33.3 

163 

107.8 

1,547 

1,834 

.85 

8.92 

72.9 

30.9 

31.4 

166 

106.8 

1,515 

1,820 

.83 

8.81 

Average  .  . 

10.5 

72.8 

26.9 

31.6 

148 

108.2 

1,506 

1,766 

.85 

8.59 

May8  

75.9 

22.3 

30.1 

112.4 

1,525 

1,742 

.88 

8.54 

76  1 

23.9 

31.1 

112.0 

1,534 

1,777 

.87 

8.68 

76  5 

24  3 

31.4 

111.8 

1,564 

1,820 

.86 

8.87 

76  7 

24  7 

32.5 

112.0 

1,589 

1,855 

.86 

9.04 

77  0 

25  7 

32.9 

111.4 

1,548 

1,911 

.81 

9.20 

77  0 

26.6 

34.1 

111.2 

1,593 

1,913 

.84 

9.28 

Average.  . 

10  5 

76  5 

24  6 

32.0 

111.8 

1,559 

1,836 

.85 

8.93 

May  22  

66.5 

26.2 

36.8 

134 

104.6 

1,783 

2,014 

.89 

9.89 

66.3 

27.2 

36.9 

148 

106.6 

1,735 

2,028 

.86 

9.89 

65.7 

28.5 

37.5 

154 

106.6 

1,741 

2,042 

.85 

9.93 

66.3 

29.0 

39.0 

164 

108.4 

1,787 

2,077 

.86 

10.13 

Average  .  . 

15.3 

66.2 

27.7 

37.6 

150 

106.6 

1,762 

2,040 

.86 

9.95 

70 


METABOLISM   DURING   WALKING. 


TABLE  14. — Metabolism  of  T.  H.  H.  during  grade  walking  in  experiments  without  food. 

(Values  per  minute.) 


Date. 

Grade. 

Dis- 
tance. 

Aver- 
age 
respi- 
ration- 
rate. 

Average 
pul- 
monary 
venti- 
lation 
(re- 
duced). 

Aver- 
age 
pulse- 
rate. 

No.  of 

steps. 

Car- 
bon 
di- 
oxide. 

Oxy- 
gen. 

Res- 
pira- 
tory 
quo- 
tient. 

Heat 
(com- 
puted). 

1915. 
Mar.  24  

p.  ct. 

meters. 
63.4 

15.9 

liters. 
16.7 

114 

97.4 

c.  c. 

1,028 

c.  c. 
1,136 

0.91 

cals. 
5.61 

62.3 

16.5 

17.3 

120 

98.0 

1,017 

1,173 

.87 

5.73 

62.1 

17.0 

16.7 

121 

98.0 

974 

1,153 

.85 

5.61 

Average  .  . 

10.3 

62.6 

16.5 

16.9 

118 

97.8 

1,006 

1,154 

.87 

5.64 

Mar.  26 

63.4 

16.6 

17.3 

113 

96.2 

1,065 

1,174 

.91 

5.79 

64.3 

16.7 

17.5 

117 

100.6 

1,067 

1,196 

.89 

5.87 

64.1 

17.3 

18.0 

120 

100.2 

1,064 

1,219 

.88 

5.97 

63.9 

17.8 

18.0 

126 

96.6 

1,046 

1,251 

.84 

6.07 

Average  .  . 

10.3 

63.9 

17.1 

,17.7 

119 

98.4 

1,061 

1,210 

.88 

5.93 

Mar  30 

62.1 

18.4 

18.8 

101.6 

1,057 

1,178 

.90 

5.80 

61.0 

19.2 

18.8 

117 

99.8 

1,011 

1,166 

.87 

5.70 

61.3 

19.4 

19.1 

101.4 

1,014 

1,222 

.83 

5.91 

Average  .  . 

10.2 

61.5 

19.0 

18.9 

117 

100.9 

1,027 

1,189 

.86 

5.80 

Apr.  5          .  . 

62.3 

17.9 

18.4 

126 

103.4 

1,056 

1,241 

.85 

6.03 

63.2 

19.0 

18.8 

132 

104.2 

1,050 

1,309 

.80 

6.28 

63.7 

18.8 

18.9 

102.8 

1,039 

1,339 

.78 

6.40 

Average  .  . 

10.4 

63.1 

18.6 

18.7 

129 

103.5 

1,048 

1,296 

.81 

6.24 

Apr.  6  .   ... 

58.4 

17.6 

17.5 

118 

99.0 

1,019 

1,135 

.90 

5.59 

59.3 

19.0 

18.1 

123 

100.8 

1,021 

1,144 

.89 

5.62 

60.2 

19.0 

17.9 

125 

100.6 

1,012 

1,167 

.87 

5.70 

59.4 

19.0 

18.1 

129 

101.6 

968 

1,268 

.77 

6  04 

60.1 

20.0 

17.9 

136 

103.2 

1,006 

1,231 

.82 

5.94 

60.4 

21.0 

18.3 

147 

103.6 

4,009 

1,275 

.79 

6.11 

Average  .  . 

10.4 

59.6 

19.3 

18.0 

130 

101.5 

1,006 

1,203 

.84 

5.83 

Apr.  7     

56.1 

18.7 

17.4 

121 

98.6 

957 

1,118 

.86 

5.45 

56.4 

18.8 

17.7 

118 

100.4 

953 

1,130 

.85 

5  50 

56.3 

18.1 

17.1 

124 

99.8 

932 

1,134 

.82 

5  47 

56.6 

18.4 

17.0 

133 

100.6 

941 

1,152 

.82 

5.56 

56.5 

18.6 

17.2 

139 

101.0 

931 

1,160 

.80 

5.57 

57.2 

17.9 

17.2 

146 

103.6 

968 

1,207 

.80 

5  79 

57.6 

18  6 

17.6 

103.6 

979 

1,206 

81 

5  80 

Average  .  . 

10.4 

56.7 

18.4 

17.3 

130 

101.1 

952 

1,158 

.82 

5.59 

Apr.  8 

67.8 

18.6 

19.3 

105.4 

1,115 

1,300 

86 

6  34 

68.0 

19.4 

19.7 

105.6 

1,089 

1,277 

86 

6  23 

67.5 

19.9 

19.7 

104  8 

1  088 

1  308 

83 

6  33 

67.9 

20.8 

20.3 

103.2 

1,100 

1,322 

.83 

6  40 

68.6 

21.2 

20.6 

103.4 

1,090 

1,347 

81 

6  48 

69.0 

20.5 

20.4 

104.4 

1,079 

1,374 

79 

6  58 

Average  .  . 

10.4 

68.1 

20.1 

20.0 

104.5 

1,094 

1,321 

.83 

6.39 

Apr.  16  

63.9 

14.2 

16.7 

100 

101.4 

972 

1,178 

83 

5  70 

65.0 

15.5 

17.0 

102 

100.0 

1,011 

1,204 

84 

5  84 

64.8 

17.0 

16.9 

104 

99.2 

992 

1,196 

83 

5  79 

65.0 

17.7 

16.6 

107 

100.6 

981 

1,204 

82 

5  81 

65.4 

18.1 

17.5 

116 

101.6 

985 

1  232 

80 

5  91 

65.9 

18.8 

17.7 

119 

101  0 

998 

1  245 

80 

5  98 

Average  .  . 

10.3 

65.0 

16.9 

17.1 

108 

100.6 

990 

1,210 

.82 

5.84 

STATISTICS   OF   EXPERIMENTS. 


71 


TABLE  15. — Metabolism  of  W.  K.  during  grade  walking  in  experiments  without  food.     (Values 

per  minute.) 


Date. 

Grade 

Dis- 
tance. 

Aver- 
age 
respi- 
ration 
rate. 

Aver- 
age 
pul- 
monary 
venti- 
lation 
(re- 
duced) 

Aver- 
age 
pulse- 
rate. 

No.  of 

steps. 

Car- 
bon 
di- 
oxide. 

Oxy- 
gen. 

Res- 
pira- 
tory 
quo- 
tient. 

Heat 
(com- 
puted). 

1915. 
Mar.  4  ... 

p.  ct. 

meters 
69.5 

24.0 

liters. 
16.9 

114.8 

c.  c. 
733 

c.  c. 
810 

0.91 

cals. 
4.00 

68.9 

24.8 

15.7 

113.5 

691 

770 

.90 

3.79 

68.9 

25.5 

16.3 

114.0 

701 

782 

.90 

3.85 

Average 

3.6 

69.1 

24.8 

16  3 

114  1 

708 

787 

.90 

3  88 

Mar.  5  

67.5 

22.1 

11.0 

116.3 

666 

758 

.88 

3.71 

68.3 

23.0 

13.5 

116.0 

643 

763 

.85 

3.71 

68.3 

23.1 

13.5 

116.0 

638 

767 

.83 

3.71 

68.4 

22.8 

13  1 

114.2 

625 

775 

.81 

3.73 

Average 

3.6 

68.1 

22  8 

12  8 

115.6 

643 

766 

.84 

3  72 

Mar.  8  

68.9 

22.7 

14.9 

118.2 

678 

790 

.86 

3.85 

69.6 

27.8 

16.0 

118.6 

671 

848 

.79 

4.06 

70.1 

28.3 

16  6 

117.6 

688 

812 

.85 

3.95 

Average 

3.9 

69.5 

26.3 

15.8 

118.1 

679 

817 

.83 

3.95 

Mar.  9  .... 

70.0 

22.6 

14  0 

117.8 

655 

803 

.82 

3.87 

70.5 

27.9 

14  8 

117.6 

652 

802 

.81 

3.86 

Average 

3.9 

70.3 

25.3 

14.4 

117.7 

654 

803 

.81 

3.86 

Mar.  23  

63.2 

23.7 

20.2 

110 

108.2 

872 

1,004 

.87 

4.91 

66.6 

25.0 

20  3 

114 

108  4 

857 

*4  81 

63.2 

26.1 

20.2 

117 

109.4 

871 

1,024 

.85 

4.98 

63.5 

26.5 

20  5 

119 

107.6 

910 

1,032 

.88 

5.06 

Average  .  . 

9.2 

64.1 

25.3 

20.3 

115 

108.4 

878 

1,020 

.86 

4.97 

Mar.  25..    . 

60.9 

23.6 

19  5 

120 

104.6 

861 

1,028 

.84 

4.99 

60.8 

24.8 

19  8 

120 

103  6 

855 

1,050 

.82 

5.07 

60.8 

25.0 

20.0 

128 

100.8 

856 

1,042 

.82 

5.03 

Average  .  . 

10.7 

60.8 

24.5 

19.8 

123 

103.0 

857 

1,040 

.82 

5.02 

Mar.  31  

58.3 

24.7 

18.3 

113 

104.0 

837 

978 

.86 

4.77 

58.3 

25.4 

18  2 

123 

105.4 

843 

987 

.86 

4.81 

58.2 

25.1 

18  2 

125 

103.4 

835 

995 

.84 

4.83 

58.9 

26.1 

18  4 

129 

104.4 

929 

1,007 

.93 

4.99 

Average  .  . 

10.3 

58.4 

25.3 

18.3 

123 

104.3 

861 

992 

.87 

4.85 

Apr.  2  

57.6 

24.6 

20  0 

108 

98.9 

860 

964 

.89 

4.74 

57.9 
57.9 
58.8 
58.7 
58.6 
57.7 

24.4 
24.9 
25.0 
25.1 
24.5 
25.1 

19.8 
19.6 
20.1 
17.9 
17.8 
19.2 

108 

112 
112 
116 
115 

99.6 
100.0 
100.6 
101.6 
99.8 
99.0 

817 
812 
846 
825 
802 
816 

981 
1,105 
988 
1,098 
1,005 
992 

.83 
.74 
.86 
.75 
.80 
.83 

4.75 
5.22 
4.82 
5.20 
4.83 
4.80 

Average  .  . 

10.3 

58.2 

24.8 

19.2 

112 

99.9 

825 

1,019 

.81 

4.90 

'Computed  from  the  carbon  dioxide  for  the  period  and  the  average  of  the  respiratory  quotient* 
for  the  day. 


72 


METABOLISM    DURING   WALKING. 


TABLE  15. — Metabolism  of  W.  K.  during  grade  walking  in  experiments  without  food.     (Values 

per  minute.) — Continued. 


Date. 

Grade 

Dis- 
tance. 

Aver- 
age 
respi- 
ration 
rate. 

Aver- 
age 
pul- 
monary 
venti- 
lation 
(re- 
duced) 

Aver- 
age 
pulse- 
rate. 

No.  of 

steps. 

Car- 
bon 
di- 
oxide. 

Oxy- 
gen. 

Res- 
pira- 
tory 
quo- 
tient. 

Heat 
(com- 
puted). 

1915. 
Apr.  12  

p.  ct. 

meters 
59.5 

24.4 

liters. 
18.5 

118 

107.6 

c.  c. 
833 

c.  c. 
1,025 

0.82 

cals. 
4.95 

59.8 

24.3 

19.7 

107.4 

846 

1,036 

.82 

5.00 

59.1 

25.3 

18.0 

106.0 

798 

1,014 

.79 

4.86 

59.1 

25.5 

19.6 

103.6 

809 

1,044 

.78 

4.99 

57.9 

24.5 

17.2 

126 

101.8 

815 

1,029 

.79 

4.93 

58.1 

24.3 

17.5 

125 

104.8 

801 

1,093 

.74 

5.15 

58.0 

23.9 

18.9 

130 

107.2 

806 

1,022 

.79 

4.89 

Average  .  . 

10.5 

58.8 

24.6 

18.5 

125 

105.5 

815 

1,038 

.79 

4.97 

Apr.  13  .  . 

58.6 

24.8 

18.5 

106.8 

801 

1,076 

.75 

5.10 

58.2 

24.4 

18.0 

105.2 

814 

982 

.83 

4.75 

58.3 

24.9 

17.5 

103.6 

820 

981 

.84 

4.76 

10  5 

58  4 

24  7 

18.0 

105.2 

812 

1,013 

.80 

4  86 

Apr.  14 

63.9 

26.3 

21.8 

112.0 

931 

1,041 

.90 

5.13 

64.5 

26.5 

21.4 

111.2 

921 

1.069 

.86 

5.21 

64  5 

27.1 

21.2 

110.0 

902 

1,051 

.86 

5  12 

64  9 

26.9 

19.6 

108.2 

921 

1,112 

.83 

5  38 

65.0 

26.5 

19.6 

106.6 

900 

1,073 

.84 

5.20 

Average 

10  5 

64.6 

26.7 

20.7 

109.6 

915 

1,069 

.86 

5  21 

Apr.  16  

64.1 

26.2 

18.7 

112 

106.4 

904 

1,063 

.85 

5.17 

64.1 

26.1 

19.1 

120 

105.8 

893 

1,016 

.88 

4.98 

64.4 

26.8 

19.2 

125 

107.4 

'  871 

1,150 

.76 

5.46 

64.1 

26.7 

18.7 

130 

108.4 

871 

1,045 

.84 

5  06 

64.4 

26.9 

18.9 

133 

106.8 

869 

1,047 

.83 

5.07 

64.9 

27.0 

18.7 

137 

108.0 

858 

1,077 

.80 

5.17 

65.2 

27.5 

19.2 

139 

108.2 

880 

1,076 

.82 

5.19 

Average  .  . 

10.3 

64.5 

26.7 

18.9 

128 

107.3 

878 

1,068 

.82 

5.15 

Apr.  20  

69.2 

26.2 

19.9 

114 

110.8 

951 

1,207 

.79 

5.78 

69.6 

26.8 

19.6 

118 

111.0 

943 

1,217 

.78 

5  81 

123 

69.1 

27.2 

18.6 

125 

108.9 

884 

(1,374) 

(.65) 

*5  41 

69.3 

27.4 

19.4 

125 

110.8 

958 

1,121 

.86 

5  46 

69.2 

27.5 

18.8 

127 

110.8 

879 

(1,349) 

(.65) 

5.38 

69.7 

27.4 

18.6 

131 

112.6 

906 

1,277 

.71 

5  99 

Average  .  . 

10.5 

69.4 

27.1 

19.1 

123 

110.8 

920 

1,206 

.76 

5.73 

Apr.  21  

70.0 

27.1 

22.6 

106 

111.2 

946 

1,158 

82 

5  59 

70.0 

27.0 

21.8 

111 

111.4 

931 

1,226 

.76 

5  83 

70.1 

28.3 

22.9 

115 

111.2 

978 

1,182 

.83 

5.72 

71.6 

28.2 

22.3 

112 

112.4 

940 

(1,499) 

(.63) 

*5  59 

72.0 

29.4 

22.9 

113 

111.8 

966 

1,154 

.84 

5.60 

Average  .  . 

10.5 

70.7 

28.0 

22.5 

111 

111.6 

952 

1,180 

.81 

5.68 

xComputed  from  the  carbon  dioxide  for  the  period  and  the  average  of  the  respiratory  quotients 
or  the  day. 


STATISTICS    OF   EXPERIMENTS. 


73 


TABLE  15. — Metabolism  of  W.  K.  during  grade  walking  in  experiments  without  food.     (Values 

per  minute.) — Continued. 


Date. 

Grade 

Dis- 
tance. 

Aver- 
age 
respi- 
ration- 
rate. 

Aver- 
age 
pul- 
monary 
venti- 
lation 
(re- 
duced). 

Aver- 
age 
pulse- 
rate. 

No.  of 

steps. 

Car- 
bon 
di- 
oxide. 

Oxy- 
gen. 

Res- 
pira- 
tory 
quo- 
tient. 

Heat 
(com- 
puted). 

1915. 
Apr.  22 

p.  ct. 

meters 
70.7 

27.9 

liters. 
21.9 

111.8 

c.  c. 
980 

c.  c. 
1,319 

0.75 

cals. 
6.25 

70.9 

28.7 

21.6 

108 

111.8 

963 

1,224 

.79 

5.86 

72.2 

29.4 

22.2 

117 

112.8 

987 

1,243 

.80 

5.97 

72.0 

29.8 

21.7 

111 

111.8 

997 

1,311 

.76 

6.23 

71.3 

29.2 

21.8 

110 

111.2 

941 

1,258 

75 

5  96 

71.7 

29.4 

21.4 

113 

111.8 

961 

1,251 

.77 

5.96 

Average  .  . 

10.5 

71.5 

29.1 

21.8 

112 

111.9 

972 

1,268 

.77 

6.04 

Apr  23 

70.7 

27.7 

22.7 

110.6 

975 

1,207 

81 

5.81 

71.2 

27.9 

22.8 

111 

111.0 

945 

1,183 

.80 

5.68 

71.4 

28.0 

22.4 

119 

111.0 

938 

1,207 

.78 

5.76 

71.3 

28.2 

21.6 

120 

110.0 

911 

1,281 

.71 

6.01 

71.8 

28.1 

22.1 

120 

110.8 

932 

1,265 

.74 

5.98 

Average  .  . 

10.5 

71.3 

28.0 

22.3 

118 

110.7 

940 

1,229 

.76 

5.84 

Apr.  26  

74.9 

28.5 

24.4 

128 

116.4 

1,055 

1,239 

.85 

6.03 

75.5 

28  8 

24.4 

133 

116.4 

1,043 

1,232 

85 

5  99 

75.9 

29.0 

24.5 

142 

116.0 

1,036 

1,250 

.83 

6.05 

76.3 

28.3 

22.0 

115.6 

1,008 

1,285 

.79 

6  15 

76.6 

29  5 

23.0 

116.2 

1,017 

1,276 

.80 

6  13 

77.5 

30.3 

23.1 

117.2 

1,064 

1,259 

.85 

6.11 

Average  .  . 

10.5 

76.1 

29.1 

23.6 

134 

116.3 

1,037 

1,257 

.82 

6.07 

Apr.  27  

76.2 

28.8 

23.2 

118 

117.2 

1,066 

1,276 

.84 

6.19 

76.9 

28.7 

23.1 

122 

115.8 

1,054 

1,288 

.82 

6.21 

77.1 

29.2 

22.8 

128 

115.8 

1,062 

1,314 

.81 

6.32 

76.9 

29.2 

23.0 

130 

115.6 

1,088 

1,206 

.91 

5.95 

77.4 

30.1 

22.7 

131 

116.0 

1,050 

1,386 

.76 

6.59 

77.8 

31.0 

23.1 

131 

116.8 

1,070 

1,280 

.84 

6.21 

Average  .  . 

10.5 

77.1 

29.5 

23.0 

127 

116.2 

1,065 

1,292 

.82 

6.23 

Apr.  28  

75.6 

28.2 

21.8 

117 

114.4 

1,039 

1,417 

.74 

6.70 

76.1 

28.3 

22.2 

117 

114.2 

1,039 

1,317 

.79 

6.31 

76.7 

28.5 

22.3 

121 

115.2 

1,044 

1,242 

.84 

6.02 

77.1 

29.8 

22.7 

127 

115.4 

1,054 

1,254 

.84 

6.08 

Average  .  . 

10.5 

76.4 

28.7 

22.2 

121 

114.8 

1,044 

1,308 

.80 

6.28 

Apr.  29  

75.1 

28.0 

23.5 

115 

113.0 

1,043 

1,249 

.84 

6.06 

75.8 

28.3 

24.1 

119 

113.8 

1,044 

1,202 

.87 

5.87 

76  0 

28  4 

24.4 

114.4 

1,051 

1,212 

.87 

5.92 

76.8 

28.7 

23.8 

127 

115.2 

1,068 

1,215 

.88 

5.95 

77.1 

28.5 

23.7 

128 

115.8 

1,048 

1,265 

.83 

6.12 

76.9 

28.8 

24.0 

115.6 

1,057 

1,311 

.81 

6.31 

Average  .  . 

10.5 

76.3 

28.5 

23.9 

122 

114.6 

1,052 

1,242 

.85 

6.04 

74 


METABOLISM   DURING   WALKING. 


TABLE  15. — Metabolism  of  W.  K.  during  grade  walking  in  experiments  without  food. 

ues  per  minute.) — Continued. 


(Val- 


Date. 

Grade. 

Dis- 
tance. 

Aver- 
age 
respi- 
ration- 
rate. 

Aver- 
age 
pul- 
monary 
venti- 
lation 
(re- 
duced). 

Aver- 
age 
pulse- 
rate. 

No.  of 

steps. 

Car- 
bon 
di- 
oxide. 

Oxy- 
gen. 

Res- 
pira- 
tory 
quo- 
tient. 

Heat 
(com- 
puted) . 

1915. 
Apr  30 

p.  ct. 

meters. 
77.7 

28.2 

liters. 
23.6 

117.4 

c.  c. 
1,047 

c.  c. 
1,253 

0.84 

cols. 
6.08 

78.8 

29.2 

24.1 

119 

119.0 

1,075 

1,297 

.83 

6.27 

79.9 

29.0 

24.4 

124 

119.8 

1,118 

1,335 

.84 

6.47 

80.2 

29.2 

24.3 

124 

119.6 

1,105 

(1,516) 

(.73) 

'6.50 

80.9 

29.1 

24.1 

125 

119.8 

1,090 

1,387 

.79 

6.64 

81.3 

29.5 

24.4 

130 

120.6 

1,106 

1,418 

.78 

6.77 

Average  .  . 

10.5 

79.8 

29.0 

24.2 

124 

119.4 

1,090 

1,338 

.81 

6.44 

77.0 

28.2 

22.3 

117.2 

1,083 

1,277 

.85 

6.21 

78.1 

27.4 

21.7 

117.2 

1,078 

1,363 

.79 

6.53 

78.4 

27.5 

21.4 

118.0 

1,080 

1,272 

.85 

6.19 

78.6 

26.8 

22.0 

117.6 

1,104 

1,267 

.87 

6.19 

79  1 

27.6 

21.3 

119.2 

1,094 

1,463 

.75 

6  93 

79.3 

27.7 

21.6 

119.0 

1,115 

1,321 

.85 

6.42 

10  5 

78  4 

27  5 

21.7 

118  0 

1,092 

1,327 

.82 

6  40 

May    5  

77.2 

27.5 

21.7 

113 

116.6 

1,097 

1,224 

.90 

6.03 

77.8 

28.2 

23.8 

117 

117.2 

1,083 

1,406 

.77 

6.70 

78.3 

28.1 

22.1 

119 

117.6 

1,090 

1,268 

.86 

6.18 

78.6 

28.2 

22.5 

120 

118.2 

1,125 

1,282 

.88 

6.28 

79.5 

28.7 

22.4 

125 

119.0 

1,104 

1,301 

.85 

6.33 

80.1 

28.9 

23.1 

133 

119.0 

1,163 

1,348 

.87 

6.57 

Average  .  . 

10.5 

78.6 

28.3 

22.6 

121 

117.9 

1,110 

1,305 

.85 

6.35 

May  10 

53.6 

23.7 

21.1 

94.8 

IjOll 

1,159 

.87 

5.66 

54  0 

24  2 

21.4 

99  8 

975 

1,174 

.83 

5  68 

55.0 

24.5 

20.9 

98.6 

1,045 

1,244 

.84 

6.03 

55.7 

24.8 

20.9 

100.2 

1,046 

1,269 

.83 

6.12 

56.0 

26.1 

21.5 

103.0 

974 

1,282 

.76 

6.09 

15  0 

54  9 

24  7 

21.1 

99  3 

1  010 

1,226 

.82 

5  92 

May  11 

57.5 

24.1 

19.8 

96.6 

935 

1,170 

.80 

5.62 

56.6 

24.7 

19.9 

98.2 

885 

1,062 

.84 

5.14 

56  6 

24.6 

19.4 

99.8 

896 

1,050 

.86 

5  11 

57.9 

24.9 

19.9 

100.6 

948 

1,073 

.89 

5.27 

58.1 

24.8 

19.0 

100.4 

908 

1,176 

.77 

5.60 

58.0 

25.7 

19.8 

102.6 

913 

1,141 

.80 

5.48 

13  0 

57  5 

24  8 

19.6 

99.7 

914 

1,112 

82 

5  37 

May  12 

58.3 

25.7 

21.0 

103.4 

928 

1,170 

.80 

5.62 

58.4 

25.9 

21.0 

105.6 

901 

1,099 

.82 

5.30 

58.6 

26.0 

21.6 

105.2 

988 

1,119 

.88 

5.48 

59  0 

26  1 

20.2 

106.2 

945 

1,109 

.85 

5.39 

58  9 

26  3 

20.0 

106.0 

893 

1,143 

78 

5  46 

59  1 

26  8 

20  0 

105  4 

907 

1   134 

80 

5.44 

13.0 

58.7 

26  1 

20  6 

105.3 

927 

1,129 

82 

5  45 

1Computed  from  the  carbon  dioxide  of  the  period  and  the  average  of  the  respiratory  quotient* 
for  the  day. 


STATISTICS   OF   EXPERIMENTS. 


75 


TABLE  15. — Metabolism  of  W.  K.  during  grade  walking  in  experiments  without  food.     (Val- 
ues per  minute.) — Continued. 


Date. 

Grade. 

Dis- 
tance. 

Aver- 
age 
respi- 
ration- 
rate. 

Aver- 
age 
pul- 
monary 
venti- 
lation 
(re- 
duced). 

Aver- 
age 
pulse- 
rate 

No.  of 

steps. 

Car- 
bon 
di- 
oxide. 

Oxy- 
gen. 

Res- 
pira- 
tory 
quo- 
tient. 

Heat 

(com- 
puted). 

1915. 
May  13 

p.ct. 

meters. 
60.4 

26.9 

liters. 
25.1 

119 

106.0 

c.  c. 
1,127 

c.  c. 
1,356 

0.83 

cats. 
6.56 

60.2 

28.4 

25.3 

125 

107.4 

1,110 

1,401 

.79 

6.71 

59.8 

29.0 

25.1 

128 

107.8 

1,116 

1,430 

.78 

6.83 

59.9 

29.3 

23.6 

105.6 

1,142 

1,382 

.83 

6  69 

59  5 

29.0 

23  0 

107.2 

1,103 

1,294 

.86 

6  31 

59  2 

28.6 

22  5 

105.0 

1,081 

1,309 

.83 

6  33 

Average  .  . 

15.0 

59.8 

28.5 

24.1 

124 

106.5 

1,113 

1,362 

.82 

6.57 

May  14 

56.8 

26.2 

25.0 

111 

104.8 

1,089 

1,219 

.89 

5.99 

54.9 

27.1 

24.1 

112 

104.8 

1,042 

1,199 

.87 

5.86 

54.8 

27.7 

24.2 

120 

103.8 

1,032 

1,193 

.87 

5.83 

55.3 

27.7 

22.3 

117 

102.2 

1,047 

1,182 

.89 

5.81 

55.2 

27.4 

21.7 

116 

104.4 

1,024 

15.70 

Average  .  . 

15.3 

55.4 

27.2 

23.5 

115 

104.0 

1,047 

1,198 

.87 

5.85 

May  17 

57.7 

27.2 

23.5 

120 

110.4 

1,115 

1,302 

.86 

6.35 

58.2 

27.9 

23.5 

126 

111.2 

1,103 

1,295 

.85 

6.30 

57.6 

28.3 

23.0 

128 

111.2 

1,098 

1,291 

.85 

6.28 

57.6 

28.0 

22.4 

129 

109.2 

1,075 

1,289 

.84 

6  25 

57.6 

28.3 

23.1 

132 

111.0 

1,074 

1,312 

.82 

6  33 

Average  .  . 

15.3 

57.7 

27.9 

23.1 

127 

110.6 

1,093 

1,298 

.84 

6.30 

May  18  

60.3 

27.5 

26.4 

115 

109.8 

1,169 

1,301 

.90 

6.41 

60.2 

27.6 

26.2 

112 

109.8 

1,156 

1,318 

.88 

6  46 

60.1 

27.9 

26.4 

118 

111.8 

1,157 

1,326 

.87 

6.48 

59.6 

27.3 

25.4 

117 

105.0 

1,142 

1,299 

.88 

6.37 

59.3 

27.6 

24.7 

117 

104.8 

1,107 

1,288 

.86 

6  28 

58.7 

27.3 

24.7 

120 

107.8 

1,099 

1,301 

.85 

6  33 

Average  .  . 

15.4 

59.7 

27.5 

25.6 

117 

108.2 

1,138 

1,306 

.87 

6.38 

May  24 

65.5 

28.2 

26.5 

129 

115.8 

1,286 

1,468 

.88 

7  19 

65.6 

28.0 

25.9 

133 

114.8 

1,279 

1,492 

.86 

7  27 

65.7 

28.7 

26.8 

136 

117.0 

1,292 

1,419 

.91 

7  00 

66.0 

28.3 

25.8 

137 

114.0 

1,292 

1,436 

.90 

7  07 

66.3 

28.4 

148 

114.6 

1,261 

^.ge 

66.6 

29.1 

25.7 

151 

115.2 

1,289 

1,468 

.88 

7  19 

Average  .  . 

15.3 

66.0 

28.5 

26.1 

139 

115.2 

1,283 

1,457 

.88 

7.14 

May  25 

66.4 

29.2 

29.3 

130 

116.6 

1,322 

1,456 

.91 

7  19 

67.4 

29.0 

29  4 

134 

116.4 

1,300 

1,502 

87 

7  34 

66.9 

28.7 

29.1 

135 

115.6 

1,304 

1,480 

.88 

7  25 

66.8 

28.5 

26.4 

134 

112.6 

1,305 

1,473 

.89 

7  24 

66.6 

28.5 

25.3 

138 

110.8 

1,258 

1,471 

.86 

7  17 

66.5 

29.4 

25.5 

143 

111.6 

1,267 

(1,668) 

(  76) 

*7  05 

Average  .  . 

15.3 

66.8 

28.9 

27.5 

136 

113.9 

1,293 

1,476 

.88 

7.23 

'Computed  from  the  carbon  dioxide  of  the  period  and  the  average  of  the  respiratory  quotients 
for  the  day. 


76 


METABOLISM   DURING   WALKING. 


TABLE  15. — Metabolism  of  W.  K.  during  grade  walking  in  experiments  without  food.     (Val- 
ues per  minute.) — Continued. 


Date. 

Grade. 

Dis- 
tance. 

Aver- 
age 
respi- 
ration- 
rate. 

Aver- 
age 
pul- 
monary 
venti- 
lation 
(re- 
duced) 

Aver- 
age 
pulse- 
rate. 

No.  of 

steps. 

Car- 
bon 
di- 
oxide. 

Oxy- 
gen. 

Res- 
pira- 
tory 
quo- 
tient. 

Heat 
(com- 
puted) . 

1915. 
May  26 

p.  ct. 

meters. 
77.6 

30.0 

liters. 
31.0 

134 

121.3 

c.  c. 
1,549 

c.  c. 
1,656 

0.94 

cols. 
8.24 

78.9 

31.0 

32.3 

143 

122.8 

1,553 

1,853 

.84 

8.99 

79.2 

31.9 

32.4 

146 

121.3 

1,578 

1,733 

.91 

8.55 

79.7 

31.1 

30.9 

143 

120.0 

1,577 

1,917 

.83 

9.28 

80.3 

32.8 

31.5 

121.3 

1,560 

1,908 

.82 

9.21 

80.7 

32.9 

32.2 

121.5 

1,573 

1,795 

.88 

8.80 

Average  .  . 

15.3 

79.4 

31.6 

31.7 

142 

121.4 

1,565 

1,810 

.86 

8.82 

May  28 

78.1 

29.9 

29.8 

128 

119.5 

1,529 

1,627 

.94 

8.09 

78.9 

30.2 

29.1 

136 

119.0 

1,478 

1,648 

.90 

8.11 

79.4 

29.8 

30.0 

138 

123.0 

1,510 

1,672 

.91 

8.25 

79.8 

28.7 

28.7 

137 

119.8 

1,517 

1,687 

.90 

8.31 

80.7 

30.6 

29.7 

147 

121.8 

1,534 

1,740 

.88 

8.53 

80.9 

31.4 

30.2 

152 

122.0 

1,552 

1,771 

88 

8.68 

Average  .  . 

15.3 

79.6 

30.1 

29.6 

140 

120.9 

1,520 

1,691 

.90 

8.33 

May  29 

79.0 

29.4 

32.1 

135 

119.0 

1,516 

1,676 

.91 

8.28 

80.0 

30.7 

33.0 

146 

122.3 

1,537 

1,721 

.90 

8.48 

80.4 

32.1 

34.3 

149 

122.5 

1,583 

1,752 

.91 

8.65 

Average  .  . 

15.3 

79.8 

30.7 

33.1 

143 

121.3 

1,545 

1,716 

.90 

8.45 

June    1  .     ... 

80.6 

29:5 

31.7 

148 

119.5 

1,570 

1,698 

.93 

8.42 

80.2 

31.7 

32.7 

155 

121.2 

1,601 

1,735 

.93 

8.61 

80.6 

32.9 

33.5 

160 

122.8 

1-,  614 

1,757 

.92 

8.69 

Average  .  . 

15.3 

80.5 

31.4 

32.6 

154 

121.2 

1,595 

1,730 

.92 

8.56 

J  une   2  

79.1 

29.9 

31.6 

140 

120.5 

1,572 

1,697 

.93 

8.42 

79.8 

31.4 

32.7 

147 

122.0 

1,579 

1,711 

.92 

8.49 

80.4 

33.0 

33.6 

151 

123.5 

1,626 

1,757 

.93 

8.71 

Average  .  . 

15.3 

79.8 

31.4 

32.6 

146 

122.0 

1,592 

1,722 

.92 

8.52 

June    7 

49.9 

25.6 

25  1 

100.8 

1,228 

1,381 

'.89 

6.78 

50.1 

26.4 

24.9 

102.6 

1,237 

1,410 

.88 

6.91 

48.8 

26.6 

25.9 

129 

102.4 

1,200 

1,372 

.88 

6.72 

47.9 

27.6 

23.4 

126 

98.0 

1,175 

1,324 

.89 

6.50 

47.8 

27.4 

24.1 

102.4 

1,150 

1,353 

.85 

6.58 

47.3 

29.0 

24.9 

139 

104.2 

1,179 

1,369 

.86 

6.67 

Average  .  . 

20.0 

48.6 

27.1 

24.7 

131 

101.7 

1,195 

1,368 

.87 

6.69 

June   8.   ... 

46.7 

26.6 

25.0 

97  4 

1  127 

1,308 

.86 

6.38 

45.1 

32.1 

25  6 

97  4 

1  095 

1,286 

.85 

6.25 

43.9 

29  1 

24  6 

95  2 

1  070 

1,257 

.85 

6.11 

50.5 

31.7 

27  7 

134 

102  4 

1  208 

1  423 

.85 

6.92 



50.4 
50.0 

29.8 
31.3 

28.0 
28.6 

141 
146 

104.2 
106.0 

1,242 
1,253 

1,451 
1,464 

.86 
.86 

7.07 
7.14 

Average  .  . 

20.0 

47.8 

30.1 

26.6 

140 

100.4 

1,166 

1,365 

.85 

6.64 

STATISTICS   OF  EXPERIMENTS. 


77 


TABLE  15. — Metabolism  of  W.  K.  during  grade  walking  in  experiments  without  food.    (Val- 
ues per  minute.) — Continued. 


Date. 

Grade 

Dis- 
tance. 

Aver- 
age 
respi- 
ration- 
rate. 

Aver- 
age 
pul- 
monary 
venti- 
lation 
(re- 
duced). 

Aver- 
age 
pulse- 
rate. 

No.  of 

steps. 

Car- 
bon 
di- 
oxide. 

Oxy- 
gen. 

Res- 
pira- 
tory 
quo- 
tient. 

Heat 
(com- 
puted) . 

1915. 
June    9  

p.  ct. 

meters. 
57.3 

28.6 

liters. 
29.6 

110.6 

c.  c. 
1,335 

c.  c. 
1,540 

0  87 

cals. 
7.53 

56.9 

29.2 

29.7 

108.8 

1,306 

1,526 

86 

7.44 

56.9 

30.9 

30.3 

111.8 

1,325 

1,577 

84 

7.65 

58.0 

30.9 

28  0 

141 

112  8 

1  308 

1  642 

80 

7  88 

57.0 

31.9 

28.0 

145 

113.4 

1,305 

1  602 

82 

7  73 

57.0 

32.7 

29.2 

149 

114  4 

1,338 

1,583 

85 

7  70 

Average  .  . 

20.0 

57.2 

30.7 

29.1 

145 

112.0 

1,320 

1,578 

.84 

7.65 

June  10  .  . 

63.4 

31.8 

34.6 

116.6 

1,497 

1,703 

88 

8.34 

63.0 

33.0 

35.3 

117.6 

1,491 

1,726 

87 

8.43 

62.9 

33.5 

36.2 

154 

118.4 

1,488 

1,719 

.87 

8.40 

64.0 

33.4 

33.7 

150 

117  0 

1,513 

1,758 

86 

8.57 

63.8 

34.0 

34.7 

159 

117.2 

1,499 

1,759 

85 

8.55 

63.4 

36.6 

35  6 

159 

117  2 

1,501 

1,741 

86 

8  49 

Average.  . 

20.0 

63.4 

33.7 

35.0 

156 

117.3 

1,498 

1,734 

.86 

8.45 

June  11  

73.2 

32.6 

39.5 

122.8 

1,787 

1,957 

.92 

9.68 

73.4 

35.8 

45  9 

123  0 

1,793 

1,978 

91 

9.76 

74  0 

35.2 

41  5 

158 

124  0 

1,795 

1  993 

90 

9.81 

69.0 

35.0 

40.0 

162 

121.5 

1,614 

1,869 

.87 

9.13 

68.3 

36.3 

42.0 

167 

122.8 

1,655 

1,860 

.89 

9.14 

Average  .  . 

20.0 

71.6 

35.0 

41.8 

162 

122.8 

1,729 

1,931 

.90 

9.51 

June  12  

73.5 

31.8 

39.9 

153 

120.3 

1,749 

1,929 

.91 

9.52 

74.6 

36.2 

42.9 

121.5 

1,765 

2,014 

.88 

9.87 

74  A 

38.4 

44.2 

162 

121.0 

1,748 

2,004 

.87 

9.79 

74.0 

34.8 

41  .0 

120  5 

1,737 

1,948 

89 

9.57 

74.0 

36.1 

42  0 

163 

123  0 

1,704 

1,974 

86 

9  62 

74.0 

37.7 

43.2 

164 

122.5 

1,725 

1,992 

.87 

9.73 

Average  .  . 

20.0 

74.1 

35.8 

42.2 

161 

121.5 

1,738 

1,977 

.88 

9.69 

June  14  

78.8 

39.4 

45  3 

158 

123.0 

1,869 

2,010 

.93 

9.97 

79.8 

39  6 

47  4 

169 

126  8 

1,906 

2,052 

.93 

10.18 

80  0 

41.1 

49  8 

174 

126  8 

1,950 

2,085 

94 

10.37 

Average  .  . 

20.0 

79.5 

40.0 

47.5 

167 

125.5 

1,908 

2,049 

.93 

10.16 

June  15  

57.2 

30.6 

37.1 

114.0 

1,646 

1,827 

.90 

9.00 

55.0 
54.6 
54.4 
53.1 
53.1 

33.9 
32.9 
34.1 
33.6 
34.2 

34.7 
33.3 
33.9 
32.8 
32.9 

141 
140 
141 
142 
145 

110.0 
109.0 
109.8 
109.4 
108.4 

1,544 
1,517 
1,534 
1,447 
1,449 

1,760 
1,751 
1,723 
1,737 
1,731 

.88 
.87 
.89 
.84 
.84 

8.62 
8.56 
8.46 
8.42 
8.40 

Average  .  . 

25.0 

54.6 

33.2 

34.1 

142 

110.1 

1,523 

1,755 

.87 

8.58 

78 


METABOLISM    DURING  WALKING. 


TABLE  15. — Metabolism  of  W.  K.  during  grade  walking  in  experiments  without  food.     (Val- 
ues per  minute.) — Continued. 


Date. 

Grade. 

Dis- 
tance. 

Aver- 
age 
respi- 
ration- 
rate. 

Aver- 
age 
pul- 
monary 
venti- 
lation 
(re- 
duced). 

Aver- 
age 
pulse- 
rate. 

No.  of 

steps. 

Car- 
bon 
di- 
oxide. 

Oxy- 
gen. 

Res- 
pira- 
tory 
quo- 
tient. 

Heat 
(com- 
puted) . 

1915. 
June  16  

p.  ct. 

meters. 
59.9 

32.9 

liters. 
41.5 

153 

114.4 

c.  c. 

1,688 

c.  c. 
1,902 

0.89 

cats. 
9.34 

58.7 

36.9 

41.5 

154 

116.0 

1,626 

1,861 

.88 

9.12 

57.4 

36.4 

41.0 

155 

114.6 

1,587 

1,837 

.87 

8.98 

51.8 

34.4 

37.2 

149 

109.4 

1,443 

1,690 

.86 

8.24 

50.9 

33.1 

35.0 

150 

107.6 

1,359 

1,657 

.82 

8.00 

50.1 

33.4 

34.6 

151 

108.6 

1,343 

1,635 

.82 

7.89 

Average  .  . 

25.0 

54.8 

34.5 

38.5 

152 

111.8 

1,508 

1,764 

.85 

8.58 

June  17  

67.6 

36.5 

48.9 

165 

122.0 

1,968 

2,118 

.93 

10.51 

66.8 

38.8 

50.7 

170 

120.0 

1,887 

2,115 

.89 

10.39 

66.4 

38.3 

50.5 

164 

117.8 

1,921 

2,077 

.93 

10.30 

66.6 

38.8 

49.7 

166 

121.8 

1,891 

2,103 

.90 

10.36 

Average  .  . 

25.0 

66.9 

38.1 

50.0 

166 

120.4 

1,917 

2,103 

.91 

10.38 

June  23  

70  5 

37  2 

52*5 

170 

123.0 

2,084 

2,045 

1.02 

110.32 

72.4 

42.7 

60.0 

181 

123.0 

2,220 

2,142 

1.04 

»10.81 

Average.  . 

25.0 

71.5 

40.0 

56.3 

176 

123.0 

2,152 

2,094 

1.03 

110.57 

Respiratory  quotient  of  1.00  used  in  computing. 

TABLE  16. — Metabolism  of  E.  D.  B.  during  grade  walking  in  experiments  without  food. 

ues  per  minute.) 


(Val- 


Date. 

Grade. 

Dis- 
tance. 

Aver- 
age 
respi- 
ration- 
rate. 

Aver- 
age 
pul- 
monary 
venti- 
lation 
(re- 
duced). 

Aver- 
age 
pulse- 
rate. 

No.  of 

steps. 

Car- 
bon 
di- 
oxide. 

Oxy- 
gen. 

Res- 
pira- 
tory 
quo- 
tient. 

Heat 
(com- 
puted) . 

1915. 
Oct.  30  

p.ct. 

meters. 
39  8 

18  6 

liters. 
13  2 

75  8 

c.  c. 

518 

c.  c. 

589 

0  88 

cals. 
2  89 

38.4 

18  9 

12.6 

74.6 

483. 

602 

.80 

2.89 

37.9 

18  8 

12.8 

75  0 

485 

593 

.82 

2.86 

37.9 

18  7 

12.8 

73  4 

488 

605 

81 

2.91 

Average  .  . 

5 

38.5 

18.8 

12.9 

74.7 

494 

597 

.83 

2.89 

Nov.    1  

49  4 

19  9 

14  6 

83  2 

581 

650 

89 

3  19 

48  8 

19  5 

14  3 

82  8 

580 

644 

90 

3  17 

48  6 

20  3 

14  7 

82  4 

573 

658 

87 

3  22 

47  8 

19  9 

14  5 

82  2 

570 

671 

85 

3  26 

Average  .  . 

5 

48.7 

19.9 

14.5 

82.7 

576 

656 

.88 

3.21 

STATISTICS   OF   EXPERIMENTS. 


79 


TABLE  16. — Metabolism  of  E.  D.  B.  during  grade  walking  in  experiments  without  food.   (Val- 
ues per  minute.) — Continued. 


Date. 

Grade 

Dis- 
tance. 

Aver- 
age 
respi- 
ration- 
rate. 

Aver- 
age 
pul- 
monary 
venti- 
lation 
(re- 
duced) 

Aver- 
age 
pulse- 
rate. 

No.  of 
steps. 

Car- 
bon 
di- 
oxide. 

Oxy- 
gen. 

Res- 
pira- 
tory 
quo- 
tient. 

Heat 
(com- 
puted). 

1915. 
Nov.  2  ... 

p.  ct. 

meters 
41.0 

19.6 

liters. 
13.3 

79.8 

c.  c. 
520 

c.  c. 
614 

0.85 

rah. 
2.99 

40.5 

20.1 

13.1 

88 

78.6 

507 

614 

.83 

2.97 

40  4 

20  4 

13.1 

79  6 

515 

631 

.81 

3.04 

41.7 

19.8 

13.0 

79.8 

513 

622 

.83 

3.01 

Average  .  . 

5 

40.9 

20.0 

13.1 

88 

79.5 

514 

620 

.83 

3.00 

Nov.  3  .    . 

43.1 

20.0 

13.8 

77.6 

536 

610 

.88 

2.99 

42  3 

20  1 

13.2 

74.6 

507 

617 

.82 

2.98 

42.1 

19.9 

13.4 

78.4 

508 

622 

.82 

3.00 

41.5 

20.3 

13.1 

77.8 

503 

626 

.80 

3.01 

Average 

5 

42.3 

20.1 

13.4 

77.1 

514 

619 

.83 

2.99 

Nov.  4. 

48.3 

20.3 

14.3 

81.6 

538 

659 

.82 

3.18 

48.5 

20.0 

14.1 

79.0 

535 

652 

.82 

3.15 

48.1 

19.9 

14.1 

79.6 

529 

645 

.82 

3.11 

47.7 

19.8 

14.0 

79.4 

534 

658 

.81 

3.17 

Average 

5 

48.2 

20.0 

14.1 

79.9 

534 

654 

.82 

3.16 

Nov.  5  . 

44.0 

20.1 

13.7 

77 

79.2 

517 

612 

.84 

2.97 

42.6 

20.3 

13.7 

81 

77.0 

508 

620 

.82 

2.99 

41.3 

19.2 

12.6 

84 

75.2 

506 

618 

.82 

2.98 

42.0 

19.4 

13.4 

86 

75.0 

506 

623 

.81 

3.00 

Average  .  . 

5 

42.5 

19.8 

13.4 

82 

76.6 

509 

618 

.82 

2.98 

Nov.  6  

49.5 

20.0 

14.4 

81 

80.6 

556 

618 

.90 

3.04 

49.1 

21.1 

15.0 

83 

80.2 

574 

638 

.90 

3.14 

47.9 

20.1 

14.1 

87 

79.2 

538 

622 

.87 

3.04 

47.9 

19.6 

13.8 

89 

79.8 

532 

611 

.87 

2.99 

46.7 

19.7 

13.8 

93 

77.6 

536 

630 

.85 

3.06 

Average  .  . 

5 

48.2 

20.1 

14.2 

87 

79.5 

547 

624 

.88 

3.06 

Nov.  8  

53.5 

21.0 

15.4 

84.4 

614 

654 

.94 

3.25 

52.3 

20.8 

15.2 

83.0 

582 

655 

.89 

3.22 

52.3 

20.8 

14.8 

86.0 

591 

669 

.88 

3.28 

51  8 

20  0 

14  8 

82.2 

572 

664 

.86 

3.24 

Average.  . 

5 

52.5 

20.7 

15.1 

83.9 

590 

661 

.89 

3.25 

Nov.  9  

55.6 

21.1 

15.0 

85.0 

583 

686 

.85 

3.34 

54.9 

20.6 

14.3 

84.4 

569 

673 

.85 

3.27 

54.6 

21.2 

14.9 

84.8 

571 

698 

.82 

3.37 

53.9 

21.0 

14.5 

83.6 

561 

687 

.82 

3.31 

Average  .  . 

5 

54.8 

21.0 

14.7 

84.5 

571 

686 

.83 

3.32 

80 


METABOLISM   DURING   WALKING. 


TABLE  16. — Metabolism  of  E.  D.  B.  during  grade  walking  in  experiments  without  food.     (Val- 
ues per  minute.) — Continued. 


Date. 

Grade. 

Dis- 
tance. 

Aver- 
age 
respi- 
ration- 
rate. 

Aver- 
age 
pul- 
monary 
venti- 
lation 
(re- 
duced). 

Aver- 
age 
pulse- 
rate. 

No.  of 
steps. 

Car- 
bon 
di- 
oxide. 

Oxy- 
gen. 

Res- 
pira- 
tory 
quo- 
tient. 

Heat 
(com- 
puted). 

1915. 
Nov.  10  

p.  ct. 

meters. 
57.3 

22.4 

liters. 
15.9 

86 

88.0 

c.  c. 

587 

c.  c. 

684 

0.86 

cals. 
3.33 

56  5 

22  9 

15  8 

87  6 

577 

694 

.83 

3.36 

54  0 

22  5 

14  9 

86  0 

546 

669 

82 

3.23 

53  7 

22  1 

14  5 

95 

85.0 

538 

654 

.82 

3.16 

Average  .  . 

5 

55.4 

22.5 

15.3 

91 

86.7 

562 

675 

.83 

3.27 

Nov.  11  

67.1 

22.9 

17  2 

96 

96.0 

666 

765 

.87 

3.74 

65  8 

23  3 

16  8 

95  6 

647 

776 

.83 

3.75 

65  9 

22  8 

17  1 

94  6 

661 

784 

84 

3.80 

65  3 

23.0 

17  3 

105 

93.8 

672 

800 

.84 

3.88 

Average  .  . 

5 

66.0 

23.0 

17.1 

101 

95.0 

662 

781 

.85 

3.80 

Nov.  12  

65  6 

23.4 

17  2 

94 

95.2 

665 

758 

.88 

3.71 

65  4 

22  9 

17  2 

95  2 

676 

789 

.86 

3.85 

65  7 

23  4 

16  9 

94  6 

654 

782 

84 

3.79 

64  8 

22  8 

16  9 

103 

94  6 

656 

782 

.84 

3.79 

Average  .  . 

5 

65.4 

23.1 

17.1 

99 

94.9 

663 

778 

.85 

3.78 

Nov.  13  

74  0 

24.5 

19  3 

99 

100.2 

761 

849 

.90 

4.18 

74  1 

23  8 

19  0 

99  4 

753 

891 

84 

4.32 

74  0 

24.1 

18  7 

99  6 

733 

882 

.83 

4.27 

74  2 

24  8 

18  3 

104 

100  2 

697 

860 

.81 

4.14 

Average  .  . 

5 

74.1 

24.3 

18.8 

102 

99.9 

736 

871 

.85 

4.24 

Nov.  15  

74  8 

23  7 

18  7 

99 

100  2 

795 

843 

.94 

4.19 

75  0 

24  9 

19  4 

101  4 

785 

865 

91 

4.27 

75  0 

24  7 

18  7 

106 

101  2 

775 

874 

.89 

4.29 

75  1 

25  3 

18  5 

108 

101  4 

772 

873 

.89 

4.29 

Average  .  . 

5 

75.0 

24.7 

18.8 

104 

101.1 

782 

864 

.91 

4.26 

Nov.  16  

70  1 

23  2 

18  3 

96 

99  2 

693 

823 

.84 

3.99 

75  1 

24  2 

18  5 

102  8 

706 

868 

.81 

4.18 

75  3 

24  3 

18  2 

102  8 

703 

871 

.81 

4.19 

74  7 

24  7 

18  1 

105 

100  6 

702 

870 

.81 

4.19 

Average  .  . 

5 

73.8 

24.1 

18.3 

101 

101.4 

701 

858 

.82 

4.14 

Nov.  17  

48  7 

23  9 

19  5 

99 

81  6 

746 

870 

.86 

4.24 

48  5 

24  4 

19  5 

81  4 

736 

889 

.83 

4.30 

47  6 

23  7 

18  7 

81  2 

738 

882 

.84 

4.28 

47  3 

25  1 

19  5 

110 

80  2 

740 

890 

.83 

4.31 

Average  .  . 

10.3 

48.0 

24.3 

19.3 

105 

81.1 

740 

883 

.84 

4.28 

Nov.  22  

42  5 

20  2 

17  0 

77  8 

693 

786 

88 

3.85 

41  5 

20  9 

16  7 

78  0 

670 

794 

.84 

3.85 

41  5 

21  4 

16  9 

77  4 

665 

817 

.81 

3.93 

41  5 

22  2 

17  2 

77  6 

673 

825 

.82 

3.98 

Average.  . 

10.3 

41.8 

21.2 

17.0 

77.7 

675 

806 

.84 

3.91 

STATISTICS   OF   EXPERIMENTS. 


81 


TABLE  16. — Metabolism  of  E.  D.  B.  during  grade  walking  in  experiments  without  food.     (Val- 
ues per  minute.) — Continued. 


Date. 

Grade 

Dis- 
tance. 

Aver- 
age 
respi- 
ratioD 
rate. 

Aver- 
age 
pul- 
monary 
venti- 
lation 
(re- 
duced) 

Aver- 
age 
pulse- 
rate. 

No.  of 

steps. 

Car- 
bon 
di- 
oxide. 

Oxy- 
gen. 

Res- 
pira- 
tory 
quo- 
tient. 

Heat 
(com- 
puted). 

1915. 
Nov.  23  

p.ct. 

meters 
57.8 

23.5 

liters. 
21.9 

102 

87.6 

c.  c. 

834 

c.  c. 
971 

0.86 

cals. 
4.73 

57.0 

24.2 

22.2 

87.4 

886 

991 

.89 

4.87 

57.1 

24.5 

21.6 

114 

87  4 

839 

1,001 

.84 

4.85 

56.8 

23.4 

21.1 

117 

86.2 

857 

1,007 

.85 

4.90 

Average  .  . 

10.0 

57.2 

23.9 

21.7 

111 

87.2 

854 

993 

.86 

4.84 

Nov.  24  

56.5 

22.2 

20.7 

100 

85.4 

835 

966 

.86 

4.71 

57.4 

23.0 

20.9 

86.0 

852 

1,011 

.84 

4.90 

58.3 

23.4 

21.7 

87.2 

873 

1,031 

.85 

5.01 

57.4 

22.4 

20.2 

116 

86.2 

839 

1,021 

.82 

4.93 

Average  .  . 

10.0 

57.4 

22.8 

20.9 

108 

86.2 

850 

1,007 

.84 

4.88 

Nov.  26  

66.1 

21.8 

21.0 

92.6 

1,027 

1,100 

.93 

5.46 

66.6 

23.1 

21.3 

94.2 

1,041 

1,118 

.93 

5.55 

66.8 

22.9 

21.3 

97.2 

1,043 

1,149 

.91 

5.67 

66.6 

23.4 

21.2 

93.2 

1,048 

1,155 

.91 

5.70 

Average  .  . 

10.0 

66.5 

22.8 

21.2 

94.3 

1,040 

1,131 

.92 

5.60 

Nov.  27  

66.1 

22.6 

22.4 

94.6 

(936) 

1,093 

1  (  .  87) 

5.34 

65.7 

24.0 

22.6 

91.6 

1,006 

1,112 

.90 

5.48 

66.0 

23.7 

21.9 

95.6 

991 

1,128 

.88 

5.53 

65.8 

23.6 

21.8 

95.8 

983 

1,147 

.86 

5.59 

65.9 

24.7 

21.9 

97.4 

980 

1,159 

.85 

5.64 

Average  .  . 

10.0 

65.9 

23.7 

22.1 

95.0 

990 

1,128 

.88 

5.53 

Nov.  29  

65.6 

24.1 

23.5 

110 

97.6 

993 

1,100 

.90 

5.42 

65.4 

24.3 

23.4 

96.6 

985 

1,135 

.87 

5.55 

65.8 

24.3 

22.7 

95.4 

988 

1,167 

.85 

5.68 

65.6 

24.1 

27.1 

132 

96.2 

962 

1,180 

.82 

5.69 

Average  .  . 

10.0 

65.6 

24.3 

24.2 

121 

96.5 

982 

1,146 

.86 

5.59 

Nov.  30  

77.6 

24.5 

26  9 

113 

100.6 

1,189 

1,345 

.88 

6.59 

78.4 

26.4 

27.2 

101.8 

1,183 

1,373 

.86 

6.69 

78.8 

25.9 

27.9 

102.0 

1,183 

1,378 

.86 

6.72 

79.0 

26.7 

28.1 

136 

102.2 

1,207 

1,402 

.86 

6.83 

Average  .  . 

10.0 

78.5 

25.9 

27.5 

125 

101.7 

1,191 

1,375 

.87 

6.72 

Dec.    1  

79.3 

24  9 

27  2 

120 

103.8 

1,200 

1,284 

.93 

6.37 



80.1 
80.6 
80.0 

26.6 
26.9 
25.9 

28.7 
28.8 
28.8 

104.4 
104.2 
105.0 

1,209 
1,201 
1,194 

1,341 
1,362 
1,397 

.90 
.88 

.85 

6.60 
6.67 
6.79 

Average  .  . 

10.0 

80.0 

26.1 

28.4 

120 

104.4 

1,201 

1,346 

.89 

6.61 

Assumed. 


82 


METABOLISM   DURING   WALKING. 


TABLE  16. — Metabolism  ofE.D.B.  during  grade  walking  in  experiments  without  food.     ( Val- 
ues per  minute.} — Continued. 


Date. 

Grade. 

Dis- 
tance. 

Aver- 
age 
respi- 
ration- 
rate. 

Aver- 
age 
pul- 
monery 
venti- 
lation 
(re- 
duced). 

Aver- 
age 
pulse- 
rate. 

No.  of 

steps. 

Car- 
bon 
di- 
oxide. 

Oxy- 
gen. 

Res- 
pira- 
tory 
quo- 
tient. 

Heat 
(com- 
puted). 

1915. 
Dec.  2  

p.  ct. 

meters. 
68.7 

25.1 

liters. 
25.0 

108 

97.4 

c.  c. 
1,063 

c.  c. 
1,117 

.95 

cals. 
5.57 

68.7 

24.7 

25.2 

117 

97.8 

1,054 

1,151 

.92 

5.70 

68.1 

24.7 

24.0 

122 

96.8 

1,038 

1,161 

.89 

5.70 

67.6 

23.4 

23.4 

124 

97.4 

1,018 

1,162 

.88 

5.69 

Average.  . 

10.0 

68.3 

24.5 

24.4 

118 

97.4 

1,043 

1,148 

.91 

5.67 

Dec.  3  

70.7 

24.7 

24.2 

112 

97.0 

1,089 

1,189 

.92 

5.88 

70.8 

26.5 

26.3 

116 

97.8 

1,084 

1,205 

.90 

5.93 

70.2 

25.0 

25.5 

120 

96.8 

1,059 

1,218 

.87 

5.95 

70.4 

25.3 

24.4 

124 

98.4 

1,065 

1,236 

.86 

5.03 

Average  .  . 

10.0 

70.5 

25.4 

25.1 

118 

97.5 

1,074 

1,212 

.89 

5.95 

Dec.  4  

44.8 

23.6 

22.2 

. 

78.8 

936 

1,020 

.92 

5.05 

44.7 

23.8 

22.1 

78.4 

916 

1,036 

.88 

5.08 

44.2 

24.5 

21.9 

78.8 

894 

1,039 

.86 

5.07 

44.0 

23.2 

21.3 

78.0 

881 

1,042 

.85 

5.07 

Average  .  . 

15.0 

44.4 

23.8 

21.9 

78.5 

907 

1,034 

.88 

5.07 

Dec.  6  

41.5 

22.6 

21.0 

101 

77.0 

866 

950 

.91 

4.69 

39.1 

22.7 

20.6 

107 

76.4 

834 

930 

.90 

4.58 

38.3 

24.0 

20  7 

108 

74.8 

819 

910 

.90 

4.48 

37.1 

23.0 

20  3 

110 

75.6 

805 

903 

.89 

4.44 

Average  .  . 

15.0 

39.0 

23.1 

20.7 

107 

76.0* 

-    831 

923 

.90 

4.54 

Dec.  7  

48.0 

24  7 

23  7 

110 

83  0 

976 

1,076 

.91 

5.31 

46.9 

26.3 

23.6 

118 

81.6 

945 

1,060 

.89 

5.21 

44.4 

25.6 

22  5 

117 

79.2 

894 

1,020 

.88 

5.00 

Average.  . 

15.0 

46.4 

25.5 

23.3 

115 

81.3 

938 

1,052 

.89 

5.17 

Dec.  8  

57.5 

25  1 

26  1 

122 

1,099 

1,247 

.88 

6.11 

58.6 

27.2 

27.0 

131 

1,102 

1,314 

.84 

6.37 

58.5 

27.4 

32.4 

134 

89.2 

1,096 

1,326 

.83 

6.42 

57.9 

26.4 

26.0 

133 

89.0 

1,088 

1,285 

.85 

6.25 

58.4 

26.4 

26  0 

89.0 

1,072 

1,340 

.80 

6.43 

59.1 

27.5 

27  3 

90.4 

1,100 

1,371 

.80 

6.58 

Average  .  . 

15.0 

58.3 

26.7 

27.5 

130 

89.4 

1,093 

1,314 

.83 

6.36 

Dec.  13  

67  3 

25  5 

28  8 

123 

98  0 

1  233 

1  396 

88 

6  84 

67  2 

26  0 

29  4 

131 

98  0 

1  234 

1,443 

.86 

7.03 

66  0 

26  1 

29  2 

138 

96  9 

1  200 

1,419 

.85 

6.90 

Average  .  . 

15.0 

66.8 

25.9 

29.1 

131 

97.6 

1,222 

1,419 

.86 

6.92 

STATISTICS   OF   EXPERIMENTS. 


83 


TABLE  16. — Metabolism  of  E.  D.  B.  during  grade  walking  in  experiments  without  food.     (Val- 
ues per  minute.) — Continued. 


Date. 

Grade. 

Dis- 
tance. 

Aver- 
age 
respi- 
ration- 
rate. 

Aver- 
age 
pul- 
monary 
venti- 
lation 
(re- 
duced). 

Aver- 
age 
pulse  - 
rate. 

No.  of 

steps. 

Car- 
bon 
di- 
oxide. 

Oxy- 
gen. 

Res- 
pira- 
tory 
quo- 
tient. 

Heat 
(com- 
puted) . 

1915. 
Dec.  14 

p.  ct. 

meters. 
73  8 

24  3 

liters. 
31  2 

113 

104  4 

c.  c. 
1,389 

c.  c. 
1  544 

0  90 

cals. 
7  60 

74  0 

27  2 

31  2 

127 

103  2 

1,368 

1  571 

87 

7.68 

73  5 

27  4 

32  7 

129 

100  8 

1,332 

1  553 

86 

7  57 

72.8 

27  9 

32  7 

129 

101.5 

1,331 

1,535 

87 

7.50 

73  1 

27  1 

30  2 

140 

102.0 

1,322 

1,616 

82 

7.80 

Average  .  . 

15.0 

73.4 

26.8 

31.6 

128 

102.4 

1,348 

1,564 

.86 

7.62 

Dec.  15  

75.0 

22.9 

28.8 

113 

105.6 

1,376 

1,575 

.87 

7.70 

75.1 

25.8 

30.3 

120 

104.8 

1,341 

1,602 

.84 

7.77 

74  9 

26.1 

30  0 

125 

105.0 

1,326 

1,592 

83 

7.70 

74  8 

24  5 

29  8 

126 

103.2 

1,344 

1,560 

86 

7.60 

75  3 

26  5 

29  5 

132 

104.2 

1,312 

1  621 

81 

7.80 

76.0 

26.9 

31.3 

136 

105.6 

1,335 

1,655 

.81 

7.97 

Average.  . 

15.0 

75.2 

25.5 

30.0 

125 

104.7 

1,339 

1,601 

.84 

7.76 

Dec.  16  

80.3 

25.4 

33.6 

124 

107.0 

1,497 

1,671 

.90 

8.23 

81.0 

26.4 

34.2 

130 

107.0 

1,480 

1,668 

.89 

8.19 

81.4 

26.4 

33.9 

107.2 

1,501 

1,738 

.86 

8.47 

80  6 

24.8 

32.0 

134 

107.0 

1  ,  460  . 

1,649 

89 

8.10 

82  2 

27  6 

33  5 

139 

107  8 

1,472 

1,767 

83 

8  55 

82  0 

27  3 

33  8 

144 

106  8 

1,476 

1  780 

83 

8  61 

Average  .  . 

15.0 

81.3 

26.3 

33.5 

134 

107.1 

1,481 

1,712 

.87 

8.37 

Dec.  17  

54.7 

24.4 

27.8 

113 

90.8 

1,204 

1,354 

.89 

6.65 

54.4 

24.4 

27.6 

119 

89.2 

1,171 

1,386 

.85 

6.74 

52.0 

24  0 

25.8 

118 

88.0 

1,110 

1,334 

.83 

6.45 

53  4 

25  2 

26.6 

123 

89.4 

1,130 

1,378 

.82 

6.65 

53  6 

23  2 

26  0 

126 

88  7 

1,130 

1,374 

82 

6.63 

52.2 

24.9 

26.6 

128 

86.2 

1,130 

1,384 

.82 

6.68 

Average  .  . 

20.0 

53.4 

24.4 

26.7 

121 

88.7 

1,146 

1,368 

.84 

6.63 

Dec.  18  

39  7 

22.2 

21  9 

77.2 

952 

1,067 

.89 

5.24 

37  8 

22  9 

21  2 

76.8 

864 

1,042 

.83 

5.04 

37  6 

24  6 

21  5 

78.2 

870 

1,044 

83 

5.05 

45.8 

23.2 

24.0 

110 

82.6 

1,037 

1,167 

.89 

5.73 

45.3 

23.3 

23.1 

110 

82.6 

982 

1,190 

.83 

5.76 

44.4 

23.8 

22.9 

108 

82.4 

970 

1,170 

.83 

5.66 

Average  .  . 

20.0 

41.8 

23.3 

22.4 

109 

80.0 

946 

1,113 

.85 

5.41 

Dec.  20  .  . 

65  6 

24  9 

33  4 

119 

100  2 

1,523 

1,614 

94 

8  03 

65.8 

24.9 

33.4 

127 

99.6 

1,499 

1,634 

.92 

8.09 

66.0 

26.1 

34.6 

131 

100.2 

1,491 

1,641 

.91 

8.10 

66.4 

24.9 

34.4 

100.6 

1,521 

1,626 

.94 

8.09 

67.5 

25.7 

34.8 

102.6 

1,521 

1,735 

.88 

8.50 

67.1 

25.4 

34.1 

101.0 

1,514 

1,748 

.87 

8.54 

Average  .  . 

20.0 

66.4 

25.3 

34.1 

126 

100.7 

1,512 

1,666 

.91 

8.22 

84 


METABOLISM   DURING  WALKING. 


TABLE  16. — Metabolism  of  E.  D.  B.  during  grade  walking  in  experiments  without  food.     (Val- 
ues per  minute.) — Continued. 


Date. 

Grade 

Dis- 
tance 

Aver- 
age 
respi- 
ration 
rate. 

Aver- 
age 
pul- 
monary 
venti- 
lation 
(re- 
duced) 

Aver- 
age 
pulse- 
rate. 

No.  of 

steps. 

Car- 
bon 
di- 
oxide. 

Oxy- 
gen. 

Res- 
pira- 
tory 
quo- 
tient. 

Heat 
(com- 
puted). 

1915. 
Dec.  21  

p.  ct. 

meters 
69  4 

25  5 

liters. 
35  4 

103  0 

c.  c. 
1  602 

c.  c. 
1  706 

0  94 

cals. 
8.48 

70.5 

26.1 

35  7 

106  4 

1,602 

1,808 

.89 

8.88 

70.9 

26.4 

39  8 

105  4 

1,584 

1,839 

.86 

8.97 

Average  . 

20.0 

70.3 

26.0 

37.0 

104.9 

1,596 

1,784 

.90 

8.78 

Deo.  22  

69  4 

24  6 

33  4 

104  4 

1  544 

1,715 

90 

8.44 

69  5 

26  6 

34  4 

104  8 

1  550 

1,746 

89 

8.58 

71  2 

25  8 

34  7 

106  6 

1  569 

1  784 

88 

8.74 

Average  .  . 

20.0 

70.0 

25.7 

34.2 

105  3 

1,554 

1,748 

.89 

8.59 

Dec.  31  

79  6 

24  9 

41  6 

109  8 

2  025 

2,217 

91 

10.94 

80.6 

30.3 

46  1 

110  6 

2,058 

2,322 

.89 

11.41 

Average  .  . 

20.0 

80.1 

27.6 

43.9 

110  2 

2,042 

2,270 

.90 

11.18 

1916. 
Jan.  1  

79  3 

26  9 

41  3 

110  0 

1  949 

2,162 

90 

10.65 

80  1 

27  7 

43  8 

112  6 

2  001 

2  281 

88 

11.18 

81  6 

28  1 

47  0 

112  6 

2  080 

2  373 

88 

11.63 

Average  .  . 

20.0 

80.3 

27.6 

44.0 

111.7 

2,010 

2,272 

.88 

11.13 

Jan.  3  

43.1 

23  4 

27  5 

85  6 

1   184 

1  453 

82 

7.01 

42.5 

24.1 

31  8 

84  0 

1,181 

1,456 

.81 

7.01 

42  3 

24  0 

28  0 

85  0 

1   183 

1  444 

82 

6  97 

Average  .  . 

25.0 

42.6 

23.8 

29.1 

84.9 

1,183 

1,451 

.82 

7.00 

Jan.  4  

59  2 

24  6 

37  0 

97  2 

1  730 

1,909 

.91 

9.42 

60  5 

24  8 

37  5 

96  0 

1  705 

1  954 

87 

9.55 

60.4 

25  7 

38  7 

94  6 

1,729 

1,998 

.87 

9.76 

60.1 

29  1 

48  8 

96  2 

1,728 

1,999 

.86 

9.75 

Average.  . 

25.0 

60.1 

26.1 

40.5 

96.0 

1,723 

1,965 

.88 

9.63 

Jan.  5  

69  5 

27  2 

45  5 

105  6 

2  037 

2  281 

89 

11.20 

69.1 

28.1 

50  7 

103  4 

2,070 

2,223 

.93 

11.03 

Average  .  . 

25.0 

69.3 

27.7 

48.1 

104.5 

2,054 

2,252 

.91 

11.12 

Feb.  2  

45  3 

22  1 

30  8 

132 

86  0 

1  385 

1  558 

89 

7  65 

46.6 

22  1 

33  0 

144 

84  4 

1  500 

1,667 

.90 

8.21 

47.5 

23.7 

36.0 

159 

87.2 

1,574 

1,778 

.89 

8.73 

Average  .  . 

25.0 

46.5 

22.6 

33.3 

145 

85.9 

1,486 

1,668 

.89 

8.19 

Feb.  3  

51  6 

22  4 

32  9 

140 

91  4 

1  556 

1  730 

90 

8.52 

53.6 
52.7 

26.9 
25.0 

37.2 
35.7 

149 
156 

93.2 
91.4 

1,610 
1,560 

1,863 
1,822 

.86 
.86 

9.08 

8.88 

Average  .  . 

25.0 

52.6 

24.8 

35.3 

148 

92.0 

1,575 

1,805 

.87 

8.82 

STATISTICS   OF  EXPERIMENTS. 


85 


TABLE  16. — Metabolism  of  E.  D.  B.  during  grade  walking  in  experiments  without  food.    (Val- 
ues per  minute.) — Continued. 


Date. 

Grade. 

Dis- 
tance. 

Aver- 
age 
respi- 
ration 
rate. 

Aver- 
age 
pul- 
monary 
venti- 
lation 
(re- 
duced). 

Aver- 
age 
pulse- 
rate. 

No.  of 

steps. 

Car- 
bon 
di- 
oxide. 

Oxy- 
gen. 

Res- 
pira- 
tory 
quo- 
tient. 

Heat 
(com- 
puted). 

1916. 
Feb.  4 

p.  ct. 

meters. 
60.8 

24.1 

liters. 
39.0 

147 

100.5 

c.  c. 
1,801 

c.  c. 
1,954 

0.92 

cals. 
9.67 

62.7 

27.6 

45.3 

162 

100.0 

1,932 

2,141 

.90 

10.54 

63.2 

29  2 

50.6 

96.2 

1,976 

2,158 

.92 

10.68 

Average  .  . 

25.0 

62.2 

27.0 

45.0 

155 

98.9 

1,903 

2.084 

.91 

10.29 

Feb  5 

68.0 

26.6 

44.2 

105.4 

1,963 

2,189 

.90 

10.78 

72.1 

26.2 

52.7 

169 

103.0 

2,184 

2,385 

.92 

11.80 

73.0 

27.4 

50.3 

170 

105.8 

2,153 

2,391 

.90 

11.77 

Average  .  . 

25.0 

71.0 

26.7 

49.1 

170. 

104.7 

2,100 

2,322 

.90 

11.43 

Feb  7 

74.7 

26.5 

56.2 

111.8 

2,370 

2,506 

.95 

12.49 

76.5 

28.1 

59.1 

176 

107.5 

2,436 

2,592 

.94 

12.89 

76.4 

27.1 

57.9 

175 

108.6 

2,373 

2,489 

.95 

12.41 

Average  .  . 

25.0 

75.9 

27.2 

57.7 

176 

109.3 

2,393 

2,529 

.95 

12.61 

Feb.  8 

49.3 

23.8 

36.1 

129 

94.0 

1,626 

1,811 

.90 

8.92 

49.6 

27.7 

38.2 

135 

94.4 

1,637 

1,876 

.87 

9.17 

42.5 

26.6 

32.8 

132 

81.6 

1,373 

1,644 

.83 

7.95 

42.4 

26.6 

33.6 

136 

85.0 

1,417 

1,649 

.86 

8.04 

Average  .  . 

30.0 

46.0 

26.2 

35.2 

133 

88.8 

1,513 

1,745 

.87 

8.53 

Feb.  9 

48.8 

26.0 

36.7 

134 

97.4 

1,646 

1,838 

.90 

9.05 

50.2 

29.2 

40.0 

142 

98.2 

1,743 

1,967 

.89 

9.66 

57.3 

27.2 

44.2 

159 

100.0 

1,966 

2,203 

.89 

10.82 

57.9 

27.4 

44.8 

163 

96.0 

1,964 

2,198 

.89 

10.80 

Average  .  . 

30.0 

53.6 

27.5 

41.4 

150 

97.9 

1,830 

2,052 

.89 

10.08 

Feb.  10 

60.5 

28.9 

48.6 

152 

102.2 

2,062 

2,197 

.94 

10.93 

62.6 

28.0 

52.9 

167 

104.8 

2,211 

2,344 

.94 

11.66 

Average  .  . 

30.0 

61.6 

28.5 

50.8 

160 

103.5 

2,137 

2,271 

.94 

11.29 

Feb.  11 

69.4 

28.5 

58.6 

171 

106.5 

2,485 

2,615 

.95 

13.04 

69.1 

27.6 

58.4 

174 

108.8 

2,462 

2,597 

.95 

12.95 

69.9 

27.5 

57.2 

175 

113.2 

2,461 

2.629 

.94 

13.07 

Average  .  . 

30.0 

69.5 

27.9 

58.1 

173 

109.5 

2,469 

2,614 

.94 

13.00 

Feb.  12 

68.3 

27.6 

53.7 

152 

120.3 

2,312 

2,455 

.94 

12.21 

74.6 

29.1 

65.5 

173 

116.3 

2,629 

2,770 

.95 

13.81 

Average  .  . 

30.0 

71.5 

28.4 

59.6 

163 

118.3 

2,471 

2,613 

.95 

13.03 

Feb.  14 

67.8 

27.2 

52.2 

159 

110.8 

2,269 

2,452 

.93 

12.16 

68.8 

28.4 

56.8 

172 

108.0 

2,353 

2,510 

.94 

12.48 

Average  .  . 

30.0 

68.3 

27.8 

54.5 

166 

109.4 

2,311 

2,481 

.93 

12.31 

86 


METABOLISM   DURING   WALKING. 


TABLE  16. — Metabolism  of  E.  D.  B.  during  grade  walking  in  experiments  without  food.     (Val- 
ves per  minute.) — Continued. 


Date. 

Grade. 

Dis- 
tance. 

Aver- 
age 
respi- 
ration- 
rate. 

Aver- 
age 
pul- 
monary 
venti- 
lation 
(re- 
duced). 

Aver- 
age 
pulse- 
rate. 

No.  of 

steps. 

Car- 
bon 
di- 
oxide. 

Oxy- 
gen. 

Res- 
pira- 
tory 
quo- 
tient. 

Heat 
(com- 
puted). 

1916. 
Feb  15 

p.  ct. 

meters. 
43.1 

26.0 

liters. 
39.2 

135 

98.8 

c.  c. 

1,687 

c.  c. 

1,926 

0.88 

cals. 
9.44 

45.7 

28.1 

40.5 

145 

101.0 

1,747 

2,048 

.85 

9.96 

46.2 

29.1 

41.7 

155 

88.3 

1,761 

2,047 

.86 

9.98 

Average  .  . 

35.0 

45.0 

27.7 

40.5 

145 

96.0 

1.732 

2,007 

.86 

9.78 

Feb  16 

57.7 

28.5 

53.7 

168 

107.7 

2,300 

2,574 

.89 

12.64 

58.5 

31.1 

56  8 

176 

106.3 

2,315 

2,524 

.92 

12.49 

56.6 

29.1 

53  0 

178 

96.8 

2,185 

2,386 

.92 

11.81 

Average  .  . 

35.0 

57.6 

29.6 

54.5 

174 

103.6 

2,267 

2,495 

.91 

12.32 

Feb  17     .   .. 

62.3 

28.1 

61.5 

174 

104.8 

2,534 

2,723 

.93 

13.51 

62.5 

30.0 

62  0 

180 

101.0 

2,479 

2,726 

.91 

13.46 

Average  .  . 

35.0 

62.4 

29.1 

61.8 

177 

102.9 

2,507 

2,725 

.92 

13.48 

Feb.  18  

46.1 

28.5 

45.2 

148 

91.3 

2,013 

2,214 

.91 

10.93 

50.6 

29.4 

60  9 

161 

91.0 

2,178 

2,375 

92 

11.75 

51.8 

30.5 

59  3 

174 

87.3 

2  356 

2  505 

.94 

12.46 

Average  .  . 

40.0 

49.5 

29.5 

51.8 

161 

89.9 

2,182 

2,365 

.92 

11.70 

Feb.  19  

53.7 

29.5 

57.3 

156 

102.6 

2,385 

2,573 

.93 

12.76 

54.3 

32.8 

64  3 

168 

98.0 

2  500 

2,659 

.94 

13.22 

54.0 

31.3 

63  7 

169 

100.0 

2  468 

2  562 

96 

12.80 

Average  .  . 

40.0 

54.0 

31.2 

61.8 

164 

100.2 

2,451 

2,598 

.94 

12.92 

Feb.  21 

57.2 

31.1 

71.1 

177 

101.5 

2,656 

2,766 

.96 

13.82 

57.2 

31.1 

71  5 

177 

103.3 

2  667 

2  771 

96 

13.85 

57.0 

32  3 

73  3 

179 

98  5 

2  671 

2  728 

98 

13  70 

Average  .  . 

40.0 

57.1 

31.5 

72.0 

178 

101.1 

2,665 

2,755 

.97 

13.80 

Feb.  22  

64.9 

36.1 

84.6 

186 

102.5 

3,004 

3,104 

.97 

15.55 

65.4 

33  8 

84  4 

186 

104  3 

3  030 

3  159 

96 

15  79 

Average.. 

40.0 

65.2 

35.0 

84.5 

186 

103.4 

3,017 

3,132 

.96 

15.65 

Feb.  23  

40.6 

31.2 

55  1 

161 

95  7 

2,183 

2  446 

89 

12  01 

41  8 

29  1 

53  2 

164 

98  6 

2  234 

2  390 

93 

11  85 

44  1 

31  8 

59  9 

170 

100  0 

2  423 

2  519 

96 

12  59 

Average  .  . 

45.0 

42.2 

30.7 

56.1 

165 

98.1 

2,280 

2,452 

.93 

12.16 

Feb.  24      .   . 

42  8 

31  0 

61  4 

169 

95  8 

2  315 

2  421 

96 

12  10 

42  1 

31  1 

62  9 

173 

89  0 

2  242 

2322 

Q7 

UfiQ 

Average  .  . 

45.0 

42.5 

31.1 

62'2 

171 

92.4 

2,279 

2,372 

.96 

11.85 

STATISTICS   OF   EXPERIMENTS. 


87 


TABLE  16. — Metabolism  of  E.  D.  B.  during  grade  walking  in  experiments  without  food.     (Val- 
ues per  minute.) — Continued. 


Date. 

Grade. 

Dis- 
tance. 

Aver- 
age 
respi- 
ration- 
rate. 

Aver- 
age 
pul- 
monary 
venti- 
lation 
(re- 
duced). 

Aver- 
age 
pulse- 
rate. 

No.  of 

steps. 

Car- 
bon 
di- 
oxide. 

Oxy- 
gen. 

Res- 
pira- 
tory 
quo- 
tient. 

Heat 
(com- 
puted) . 

1916. 
Feb.  25     

p.  ct. 

meters. 
60.7 

27.2 

liters. 
45.6 

139 

103.2 

c.  c. 
2,041 

c.  c. 
2,247 

0.91 

cats. 
11.09 

60.9 

30.2 

49.6 

144 

103.2 

2,123 

2,314 

.92 

11.45 

Average  .  . 

30.0 

60.8 

28.7 

47.6 

142 

103.2 

2,082 

2,281 

.91 

11.26 

Feb.  26  

68.6 

28.4 

50.9 

148 

103.2 

2,307 

2,509 

.92 

12.41 

70.1 

32.0 

58.3 

158 

105.2 

2,467 

2,674 

.92 

13.23 

Average  .  . 

30.0 

69.4 

30.2 

54.6 

153 

104.2 

2,387 

2,592 

.92 

12.83 

Feb.  28  

66.7 

28,0 

52.0 

149 

107.6 

2,302 

2,443 

.94 

12.15 

67.1 

32.4 

57.9 

150 

107.2 

2,446 

2,573 

.95 

12.83 

Average  .  . 

30.0 

66.9 

30.2 

55.0 

150 

107.4 

2.374 

2,508 

.95 

12.50 

Feb.  29  

68.4 

31.2 

54.1 

147 

105.2 

2,232 

2,441 

.91 

12.05 

68.5 

33.0 

58.8 

158 

102.8 

2,336 

2,540 

.92 

12.57 

Average  .  . 

30.0 

68.5 

32.1 

56.5 

153 

104.0 

2,284 

2,491 

.92 

12.33 

Mar  4 

49.1 

27.6 

42.2 

131 

1,621 

1,764 

.92 

8.73 

48.6 

30.8 

44.4 

137 

1,624 

1,829 

.89 

8.98 

47.2 

29  8 

42.9 

137 

1,552 

1,751 

.89 

8.60 

49  1 

27.8 

43  4 

143 

1,625 

1,914 

.85 

9.31 

30  0 

48  5 

29  0 

43  2 

137 

1,606 

1,815 

.88 

8  89 

Mar  6 

51.1 

27.1 

45.2 

128 

1,763 

1,923 

.92 

9.52 

52  2 

29.7 

48.0 

138 

1,783 

2,013 

.89 

9.89 

52.5 

27  9 

46.9 

142 

1,800 

2,044 

.88 

10.02 

53.0 

30  0 

48.1 

150 

1,795 

2,015 

.89 

9.90 

30  0 

52  2 

28  7 

47  1 

140 

1,785 

1,999 

.89 

9  82 

Mar.  7... 

51.0 

28.2 

44.2 

132 

1,774 

1,909 

.93 

9.47 

51.1 

28.3 

44.0 

143 

1,682 

1,942 

.87 

9.49 

30  0 

51.1 

28  3 

44.1 

138 

1,728 

1,926 

.90 

9.48 

Mar.  8 

51.2 

28.1 

46.7 

139 

1,761 

1,891 

.93 

9.38 

51.2 

29.7 

47.2 

143 

1,735 

1,942 

.89 

9.54 

51  3 

29.8 

49.9 

150 

1,807 

1,961 

.92 

9.70 

52  3 

30  8 

50.8 

154 

1,766 

2,073 

.85 

10.08 

51  5 

28  7 

48.5 

152 

1,769 

2,011 

.88 

9.85 

51.7 

29.5 

47.9 

160 

1,723 

2,043 

.84 

9.91 

Average 

30  0 

51  5 

29.4 

48.5 

150 

1,760 

1,987 

.89 

9.76 

Mar.  23   ... 

62.5 

23.5 

22.3 

101 

937 

1,127 

.83 

5.45 

61  9 

24  3 

23.1 

104 

955 

1,089 

.88 

5.34 

10  0 

62  2 

23  9 

22.7 

103 

946 

1,108 

.85 

5.39 

88 


METABOLISM   DURING   WALKING. 


TABLE  16. — Metabolism  ofE.  D.  B.  during  grade  walking  in  experiments  without  food.     (Val- 
ues per  minute.) — Continued. 


Date. 

Grade. 

Dis- 
tance. 

Aver- 
age 
respi- 
ration- 
rate. 

Aver- 
age 
pul- 
monary 
venti- 
lation 
(re- 
duced). 

Aver 
age 
pulse- 
rate. 

No.  of 

steps. 

Car- 
bon 
di- 
oxide. 

Oxy- 
gen. 

Res- 
pira- 
tory 
quo- 
tient. 

Heat 
(com- 
puted). 

1916. 
Mar  24 

p.  ct. 

meters. 
57.1 

22.6 

liters. 
20.9 

96 

c.  c. 

862 

c.  c. 
1,010 

0  85 

calf. 
4  91 

56.7 

23.4 

20.3 

102 

847 

996 

85 

4  84 

Average 

8  9 

56.9 

23.0 

20.6 

99 

855 

1,003 

85 

4  88 

Apr  6 

46.3 

21.7 

20.8 

99 

770 

908 

85 

4  42 

47  4 

21  2 

19.1 

101 

784 

904 

87 

4  42 

47  3 

21  3 

18.7 

104 

773 

907 

85 

4  41 

10  0 

47  0 

21  4 

19  5 

101 

776 

906 

86 

4  42 

Apr  7 

45  6 

21.7 

19.2 

90 

757 

906 

83 

4  38 

46  5 

21  3 

19.5 

99 

767 

909 

84 

4  41 

47  2 

21  5 

19.2 

102 

773 

911 

85 

4  43 

10  0 

46  4 

21  5 

19  3 

97 

766 

909 

84 

4  41 

Apr.  8 

35  2 

20  0 

17.2 

90 

681 

795 

86 

3  88 

36  2 

20  4 

17.8 

95 

700 

777 

90 

3  83 

36  0 

21  2 

17.3 

94 

679 

781 

87 

3  82 

10  0 

35  8 

20  5 

17.4 

93 

687 

784 

88 

3  84 

Apr   14 

40  5 

21  6 

18.3 

85 

559 

667 

.84 

3  23 

40  8 

21  6 

18.3 

88 

552 

645 

86 

3  14 

39  8 

22  0 

18.2 

536 

624 

86 

3  04 

Average 

5  0 

40  4 

21.7 

18.3 

87 

549 

645 

.85 

3  14 

Apr.  15 

39  6 

20.9 

17.1 

80 

476 

543 

.88 

2  66 

40  1 

21  7 

16  9 

84 

458 

530 

86 

2  58 

39  5 

21  9 

16.9 

90 

453 

518 

.88 

2  54 

2  4 

39  7 

21  5 

17.0 

85 

462 

530 

87 

2  59 

TABLE  16a. — Average  body-temperature  and  blood-pressure  of  E.  D.  B.  during  grade  walking 
in  experiments  without  food.     (Values  per  minute.) 


Date. 

Average 
body- 
tempera- 
ture. 

Date. 

Average 
body- 
tempera- 
ture. 

Date. 

Average 
body- 
tempera- 
ture. 

1916. 

°C. 
38  39 

1916. 
Feb.  3  

°C. 
37.54 

1916. 
Feb.  5  

°C. 
37.44 

38.63 

38.03 
38  33 

37.78 

07  04. 

QC   t;i 

37  97 

37  69 

•p_u    o 

07     1Q 

37  53 

Feb.  4  

37.50 

Feb.  7  

37  61 

37.75 

38.31 

QC    7Q 

37.89 

37    fiA 

V7  4Q 

Average  

38.20 

Average  .    .  . 

37  72 

STATISTICS   OF  EXPERIMENTS. 


89 


TABLE  16a. — Average  body-temperature  and  blood-pressure  of  E.  D.  B.  during  grade  walking 
in  experiments  without  food.     (Values  per  minute.) — Continued. 


Date. 

Average 
body- 
tempera- 
ture. 

Date. 

Average 
body- 
tempera- 
ture. 

Date. 

Average 
body- 
tempera- 
ture. 

Blood- 
pres- 
sure. 

1916. 
Feb.    8  

°C. 
36.97 
37.93 
38.24 
38.31 

1916. 
Feb.  21  

°C. 
37.72 
38.05 
38.20 

1916. 
Mar.    7  

Average  .... 
Mar.  8  

Average  .... 
Mar  23 

°C. 
37.55 
37.91 

mm. 

Average  .... 
Feb.    9  

Average  .... 
Feb  22 

37.75 

37.99 

37.86 

37.57 
38.26 
37.67 
38.24 
37.90 
38.39 

38.29 

37.77 
38.37 
38.76 
38.89 

Average  .... 
Feb  23 

Average.  .  .  . 
Feb   11 

38.29 

38.11 
38.33 
38.33 

38.45 

Average  .... 
Feb  24 

38.01 

38.00 
38.25 
37.97 

37.53 
37.62 

119 
116 

Average  .... 
Feb.  12  

38.26 

Average  .... 
Mar  24 

37.92 
38.50 

37.58 

118 

38.07 

Average  .... 
Feb.  25 

37.74 
37.86 

126 
127 

37.37 
38.13 

38.21 

Average  .... 
Apr  6 

Average  .... 
Feb.  14  

37.31 
38.14 

37.80 

127 

37.75 

Average  .... 
Feb  26 

37.25 
37.53 
37.53 

122 
128 
128 

37.49 
38.47 

37.73 

Average  .... 
Apr.  7  

Average  .... 
Feb.  15  

37.25 
37.97 

37.98 

Average  .... 
Feb.  28  

37.44 

126 

37.65 
38.47 
38.74 

37.61 

36.66 
37.17 
37.15 

129 
130 
131 

Average  .... 
Feb  16 

Average  .... 
Apr  8 

37.11 

Average  .... 
Feb.  29  

38.29 

36.99 

130 

37.11 

37.76 
38.47 
38.59 

36.90 
37.09 
37.22 

137 
138 
141 

Average  .... 
Feb.  17  

36.98 
37.89 

Average  .... 
Apr.  14  

Average  .... 
Mar.  4  

38.27 

37.44 

37.07 

139 

37.68 

38.48 

37.23 
37.70 
36.70 
36.68 

37.06 
37.41 
37.30 

128 
128 
129 

Average  .... 
Feb  18 

Average.  .  .  . 
Mar.  6  

Average  .... 
Apr  15 

38.08 

37.26 

128 

37.73 
38.59 
39.03 

37.08 

Average  
Feb  19 

37.00 
37.28 
37.34 

127 
129 
127 

37.27 
38.01 
37.56 
38.12 

Average  .... 

38.45 

37.21 

128 

36.95 
37.97 
38.33 

Average  .... 

37.74 

37.75 

90  METABOLISM   DURING  WALKING. 

DISCUSSION  OF  RESULTS. 

The  data  given  in  the  preceding  section  will  be  discussed  in  the  gen- 
eral order  of  standing,  horizontal-walking,  and  grade-walking  experi- 
ments, considering  first  in  each  case  the  gaseous  metabolism  and  the 
heat-output,  then  the  physiological  effects  of  the  work  performed.  For 
such  discussion  reference  will  be  made  to  tables  in  the  statistical  section 
(see  p.  42)  from  which,  with  few  exceptions,  material  for  the  other 
tables  has  been  drawn. 

BASAL  METABOLISM. 

While  the  special  topic  of  this  report  is  not  basal  metabolism,  basal 
values  were  obtained  for  all  of  our  subjects,  usually  by  other  members 
of  the  Laboratory  staff,  in  experiments  carried  out  for  an  entirely 
different  purpose.  Ordinarily  these  values  were  determined  with  a 
respiratory- valve  apparatus  or  the  universal  respiration  apparatus,  and 
not  infrequently  with  the  clinical  respiration  apparatus.1  Many 
observations  were  made  in  the  comparison  of  the  several  methods, 
particularly  during  the  development  of  the  clinical  respiration  appa- 
ratus. The  conditions  in  all  of  the  experiments  were  those  required 
for  basal  values,  namely,  the  subject  was  in  the  lying  position,  in  a 
post-absorptive  condition,  and  with  the  greatest  possible  degree  of 
muscular  repose.  The  values  may  thus  be  considered  to  be  true  basal 
values.  The  data  for  all  of  the  subjects  except  E.  L.  F.  have  already 
been  reported  in  abstract  in  the  biometrical  analysis  of  basal  metabol- 
ism measurements  by  Harris  and  Benedict.2 

The  basal-metabolism  measurements  were  not  used  in  the  present 
study,  save  for  the  purpose  of  comparing  the  metabolism  of  the  sub- 
jects in  the  lying  position  with  the  values  for  their  metabolism  when 
they  were  standing,  to  determine  the  influence  of  the  effort  of  standing. 
(See  table  22,  p.  101.)  Since  these  measurements  of  the  basal  metab- 
olism were  most  carefully  made,  they  should  be  recorded  here,  but 
the  average  results  only  are  reported.  (See  table  17.) 

In  considering  the  values  in  table  17,  it  is  obvious  that  the  only  re- 
sults which  contribute  to  the  comparison  of  individuals  with  each  other 
are  those  which  have  been  computed  on  the  basis  of  unit  of  body-weight 
or  body-surface,  for  the  individuals  studied  had  materially  different 
body-weights.  The  respiratory  quotients  are,  for  the  most  part,  con- 
siderably above  the  quotient  normally  ascribed  to  the  average  man, 
viz,  0.82,  but  nevertheless  are  within  a  reasonable  range.  The  respira- 
tory quotient  of  H.  R.  R.  varied  considerably  in  the  individual 
experiments,  ranging  from  0.76  to  0.93.  His  average  of  0.80  is  lower 
than  that  for  any  other  subject.  Furthermore,  it  is  clear  that  H.  R.  R. 

Benedict  and  Tompkins,  Boston  Med.  and  Surg.  Journ.,  1916,  174,  pp.  857,  898,  and  939. 

'Harris  and  Benedict,  Carnegie  Inst.  Wash.  Pub.  No.  279,  1919,  pp.  42  and  43.  Only  such  of 
the  data  for  A.  J.  O.  and  H.  M.  S.  as  were  obtained  at  about  the  period  of  this  research  are  used 
for  comparison  in  this  report.  (See  table  17.) 


BASAL   METABOLISM. 


91 


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92  METABOLISM   DURING   WALKING. 

had  a  measurably  higher  pulse  than  any  of  the  other  men,  a  point 
which  should  be  borne  in  mind  in  the  later  consideration  of  the  results 
of  the  walking  experiments. 

The  heat-output  per  24  hours  per  kilogram  of  body-weight,  in  which 
an  effort  is  made  to  equalize  differences  in  body- weight,  shows  a  range 
of  22.9  to  26.7  calories.  This  compares  favorably  with  the  25.7  calories 
per  kilogram  of  body-weight  given  by  Harris  and  Benedict  as  an  average 
value  for  136  men.1  The  heat  produced  per  square  meter  of  body- 
surface,  with  the  body-surface  computed  by  the  height-weight  chart  of 
the  Du  Boises,  shows  variations  of  considerable  magnitude,  ranging 
from  776  calories  with  H.  M.  S.  to  964  calories  with  H.  R.  R.,  with  an 
average  of  893  calories.  The  average  value  given  by  Harris  and  Bene- 
dict for  the  136  men  previously  referred  to  was  925  calories  per  square 
meter  of  body-surface.  It  is  of  considerable  importance  to  note  that 
with  the  group  of  men  selected  for  use  in  treadmill  experiments,  and 
presumably  in  normal  health,  such  wide  variations  appear  in  the  heat- 
production  per  square  meter  of  body-surface. 

The  difficulty  in  predicting  the  heat-production  of  an  individual  from 
either  the  surface  area  or  the  body- weight  alone  is  clear  from  the  values 
given  in  table  17.  A  further  indication  of  the  normality  of  our 
subjects  may  be  found  in  a  comparison  of  these  basal  measurements 
with  values  computed  by  means  of  the  prediction  formula  of  Harris  and 
Benedict,2  which  is  based  upon  the  biometric  analysis  of  values  obtained 
for  136  normal  men.  This  comparison  is  made  in  table  18.3  With 
every  individual  the  predicted  heat-production  is  reasonably  close  to 
that  determined,  the  widest  deviation  being  with  H.  M.  S.,  whose  basal 
metabolism  was  91  calories  per  24  hours  less  than  the  predicted 
metabolism,  or  a  difference  of  6.2  per  cent. 

It  should  be  brought  out  here  that  we  are  not  dealing  with  a  group  of 
men  of  a  pronouncedly  athletic  temperament.  The  only  man  who 
could  logically  be  classed  as  an  athlete  was  A.  J.  0.,  who  was  a  semi- 
professional  baseball  player.4  In  an  earlier  study,  in  which  the  meta- 
bolism of  athletes  and  normal  individuals  was  compared,5  the  evidence 
was  reasonably  clear  that  athletes  as  a  group  show  a  higher  metabolism 
than  do  normal  individuals,  although  the  original  estimate  of  the 
influence  of  athletic  build  and  habit  upon  the  metabolism  was  somewhat 
reduced  by  a  subsequent  careful  biometric  analysis.6  From  the  values 
given  in  table  18,  it  is  evident  that  the  agreement  between  the  predicted 
and  the  determined  heat-output  is  close  enough  to  preclude  the  con- 
karris  and  Benedict,  Carnegie  Inst.  Wash.  Pub.  No.  279,  1919,  p.  204. 

zHarris  and  Benedict,  Ibid.,  p.  227. 

'It  should  be  stated  that  the  subjects  of  this  study  on  the  effect  of  walking  were,  most  of  them, 
used  for  obtaining  the  data  employed  by  Harris  and  Benedict.  In  other  words,  the  predicted 
values  given  in  table  18  are  not  independent  of  the  derivation  of  the  formula,  but  were  a  part  of 
the  results  obtained  for  the  group  of  136  men  from  which  the  formula  was  computed. 

*This  subject  was  used  by  Benedict  and  Murschhauser  (Carnegie  Inst.  Wash.  Pub.  No.  231, 
1915),  who  report  other  data  concerning  him. 

'Benedict  and  Smith,  Journ.  Biol.  Chem.,  1915,  20,  p.  342. 

'Harris  and  Benedict,  Carnegie  Inst.  Wash.  Pub.  No.  279,  1919,  p.  245. 


BASAL   METABOLISM. 


93 


tention  that  the  athletic  habits  of  these  individuals  were  sufficient 
for  them  to  acquire  strictly  athletic  characteristics.  Almost  no  evi- 
dence of  a  consistently  higher  metabolism  in  the  determined  figures  of 
this  group  may  be  seen,  but  two  subjects  showing  plus  values.  While 
we  are  somewhat  surprised  that  greater  differences  are  not  noted 
between  the  predicted  and  the  determined  metabolism,  the  results  are 
perhaps  to  be  expected  when  it  is  considered  that  these  men  were  not 
primarily  athletes.  The  usefulness  of  the  Harris  and  Benedict  formula 
for  predicting  the  metabolism  with  fairly  homogeneous  material  is  here 
demonstrated,  and  the  results  confirm  the  recent  test  of  the  formula  in 
the  prediction  of  the  metabolism  of  a  group  of  12  normal  men,  when  it 
was  found  that  the  average  for  the  predicted  total  heat-output  was 
within  +1.1  per  cent  of  the  average  measured  value.1 

TABLE  18. — Heat-production  of  subjects  in  lying  position  and  without  food,  as  computed  from 
respiration  experiments  and  as  predicted  by  the  use  of  the  Harris  and  Benedict  formula. 


Subject. 

Heat  per  24  hours. 

Computed  heat  greater 
(+)  or  less  (—  )  than 
predicted. 

Computed 
from  respi- 
ration ex- 
periments. 

Predicted  by 
use  of  Harris 
and  Bene- 
dict formula. 

Total 
difference. 

Per- 
centage 
difference. 

A.  J.  O  

cals. 
1,728 
1,860 
1,457 
1,310 
1,506 
1,721 
1,670 
1,382 

cola. 
1,720 
1,826 
1,476 
1,358 
1,560 
1,781 
1,735 
1,473 

cats. 
+  8 
+34 
-19 
-48 
-54 
-60 
-65 
-91 

+0.5 
+1.9 
-1.3 
-3.5 
-3.5 
-3.4 
-3.7 
-6.2 

H.  R.  R  

T.  H.  H  

W.  K  

E.  D.  B.  .  . 

J.  H.  G  

E.  L.  F  

H.  M.  S  

Average  

1,579 

1,616 

-37 

-2.4 

We  believe  that  the  results  in  tables  17  and  18  show  that  we  are 
dealing  with  normal  individuals,  and  that  these  basal-metabolism 
values  may  be  considered  as  of  physiological  importance  and  their  use 
hi  subsequent  comparisons  with  the  results  of  other  experiments  is 
entirely  justifiable.  It  is  to  be  regretted  that  a  more  extensive  analysis 
of  basal  measurements  for  these  subjects,  covering  a  greater  length  of 
time  and  perhaps  for  different  seasons  of  the  year,  can  not  be  made  here, 
although  other  basal  data  for  some  of  the  subjects  have  actually  been 
collected.  Such  an  analysis  has  recently  been  made  by  Dr.  J.  Arthur 
Harris.2 


Benedict,  Miles,  Roth,  and  Smith,  Carnegie  Inst.  Wash.  Pub.  No.  280,  1919,  p.  521. 
2Harris  and  Benedict,  Journ.  Biol.  Chem.,  1921,  46,  p.  257. 


94  METABOLISM    DURING  WALKING. 

EXPERIMENTS  WITH  SUBJECT  STANDING. 
METABOLISM  DURING  STANDING. 

As  the  metabolism  during  standing  has  been  generally  taken  as  a- 
basis  for  comparison  in  computing  the  increments  due  to  the  muscular 
effort  of  walking,  determinations  of  the  metabolism  of  the  subjects 
under  these  conditions  were  made  from  time  to  time  as  the  research 
progressed.  When  superimposed  factors  affecting  metabolism  but 
little,  such  as  the  ingestion  of  food,  body-posture,  etc.,  are  to  be  studied, 
basal  experiments  are  needed  with  each  comparison,  but  in  walking  and 
other  muscular- work  experiments,  when  the  superimposed  factor  result* 
in  a  large  increase  in  the  metabolism,  an  average  base-line,  either  for  the 
lying  metabolism  or  the  standing  metabolism,  may  properly  be  used,  as 
slight  differences  from  day  to  day  in  the  basal  metabolism  are  not 
relatively  important.  Thus,  for  W.  K.  and  E.  D.  B.,  metabolism 
experiments  with  the  subject  standing  were  made  on  14  and  71  days, 
respectively,  these  experiments  varying  in  length  from  one  to  six 
periods  each.  The  daily  average  values  were  used  for  computing  the 
increase  in  the  metabolism  during  the  walking  experiments.  Such 
experiments  made  at  intervals  during  a  period  of  several  months  per- 
mitted the  observation  of  any  changes  in  the  factors  recorded  which 
might  be  attributed  to  practice  or  to  seasonal  causes.  The  smaller 
amount  of  data  obtained  with  the  other  subjects  is  used  more  especially 
for  comparison  with  these  values  for  W.  K.  and  E.  D.  B. 

CARBON-DIOXIDE  ELIMINATION. 

The  carbon  dioxide  eliminated  per  minute,  by  the  subjects  while 
standing  is  given  in  tables  3  to  7  for  each  period,  together  with  the  daily 
averages.  (See  pp.  43  to  55.)  The  values  for  H.  R.  R.  for  March  20r 
1915,  which  was  the  first  day  of  experimenting  with  this  subject,  are  sa 
much  larger  than  those  of  the  other  days  that  they  have  not  been  included 
in  the  general  average  for  this  subject.  The  average  for  the  carbon 
dioxide  eliminated  per  minute  in  the  two  days  remaining  is  216  c.  c. 

With  W.  K.,  standing  experiments  were  made  on  14  days,  the  carbon- 
dioxide  elimination  varying  from  an  average  of  174  c.  c.  per  minute  on 
March  11  to  200  c.  c.  per  minute  on  March  13,  1915.  The  average  for 
the  14  days  is  186  c.  c.  per  minute. 

In  the  71  days  on  which  standing  experiments  were  made  with 
E.  D.  B.,  there  were  10  days  in  February  1916  when  the  experiment  had 
but  one  period,  and  on  3  days  in  the  same  month  and  1  each  in  Decem- 
ber 1915  and  April  1916  there  were  but  two  periods.  On  the  other 
experimental  days  there  were  three  or  more  periods.  The  daily 
average  for  the  71  days  ranged  from  a  minimum  of  181  c.  c.  per  minute 


EXPERIMENTS    WITH    SUBJECT    STANDING.  95 

on  October  27,  1915,  to  a  maximum  of  225  c.  c.  on  February  21,  1916. 
The  maximum  of  225  c.  c.  per  minute  on  February  21,  1916,  is  the 
maximum  of  a  group  of  high  values  for  carbon-dioxide  elimination  after 
several  days  of  somewhat  strenuous  exercise  in  walking  at  40  per  cent 
grade.  Moreover,  it  was  obtained  in  a  single  period,  and  therefore  may 
not  fairly  represent  the  daily  average,  but  has  been  included  with  the 
data  for  the  other  days  in  averaging. 

The  daily  average  for  the  71  days  of  experimenting  with  this  subject 
is  199  c.  c.  per  minute.  A  direct  comparison  of  the  carbon-dioxide 
values  from  day  to  day  can  only  be  made  with  due  regard  to  changes 
in  body-weight.  These  actually  did  take  place,  but  the  average  value 
for  the  whole  series,  i.  e.,  199  c.  c.,  is  to  be  considered  as  referable  to  a 
body-weight  varying  only  from  57  to  59  kg. 

OXYGEN  CONSUMPTION. 

As  with  the  carbon-dioxide  elimination,  the  apparently  abnormal 
values  for  H.  R.  R.  obtained  on  the  first  day  of  experimenting  with 
him  are  not  included  in  the  daily  average  for  this  subject.  The  aver- 
age for  the  two  days  remaining  is  281  c.  c.  per  minute.  The  daily 
average  oxygen  consumption  for  W.  K.  varied  from  212  c.  c.  on  4  days 
to  257  c.  c.  per  minute  on  March  17,  1915.  The  average  was  228  c.  c. 
for  the  14  days  when  standing  experiments  were  made.  In  the  71  days 
with  E.  D.  B.,  the  average  oxygen  consumption  for  the  day  was  240  c.  c. 
per  minute,  with  range  from  206  c.  c.  on  November  18, 1915,  to  288  c.  c. 
on  February  23,  1916.  The  daily  averages  for  this  subject  show  two 
distinct  periods,  the  values  being  lower  from  October  to  December, 
and  considerably  higher  after  the  Christmas  recess  and  during  the 
spring  months.  During  this  period  E.  D.  B.  gained  in  body-weight, 
and  as  these  figures  represent  the  total  oxygen  consumption,  it  would 
appear  that  his  standing  metabolism  was  increased.  When,  however, 
allowance  is  made  for  this  increase  in  weight,  as  is  done  in  table  21 
(see  p.  99),  it  is  seen  that  his  metabolism  per  kilogram  of  body- weight 
is  but  slightly  greater. 

RESPIRATORY  QUOTIENT. 

The  average  respiratory  quotients  for  the  subjects  standing,  as 
given  in  tables  3  to  7,  are  what  would  be  expected  for  men  of  this  class. 
The  relatively  low  average  value  of  0.77  for  H.  R.  R.  may  possibly  be 
explained  by  the  fact  that  this  man  was  earning  his  way  through  col- 
lege and  acted  as  a  waiter  in  a  college  commons.  The  report  of  the 
meals  taken  previous  to  each  experiment  showed  that  he  was  living 
very  frugally. 

The  variations  in  the  respiratory  quotient  from  period  to  period  are, 
on  the  whole,  not  excessive.  While  there  were  some  discrepancies, 
these  might  be  expected  with  so  large  a  number  of  determinations, 


96  METABOLISM   DURING   WALKING.    . 

and  it  is  believed  that  they  are  eliminated  in  averaging.  The  data 
show  a  tendency  for  the  quotients  in  the  first  periods  of  the  day  to 
run  a  little  higher,  possibly,  than  in  the  succeeding  periods,  although 
the  number  of  such  periods  is  not  sufficient  to  make  any  deduction 
therefrom  justifiable.  The  respiratory  quotients  for  the  71  days  with 
E.  D.  B.  have  an  average  daily  value  of  0.84  in  the  period  from  October 
4  to  December  22,  1915,  as  compared  with  0.82  during  the  period 
from  March  1  to  April  15,  1916.  On  February  23,  the  day  following 
his  most  severe  walking  test  with  an  oxygen  consumption  of  3,132  c.  c. 
per  minute  (see  table  16,  p.  86),  there  was  a  marked  fall  in  his  respi- 
ratory quotient,  which  may  have  been  due  to  the  after-effects  of  the 
vigorous  exercise  of  the  preceding  day.  Zuntz  and  Schumburg1  and 
Durig2  have  noted  that  the  respiratory  quotients  tend  to  fall  during 
periods  of  exercise  and  that  this  effect  is  also  apparent  on  the  following 
day.  The  respiratory  quotient  of  February  23  is,  however,  based  on 
but  one  period.  (See  table  6,  page  50.) 

The  average  respiratory  quotients  obtained  with  these  five  men  in 
the  standing  positions  are  as  follows:  A.  J.  O.,  0.84;  H.  R.  R.,  0.77; 
T.  H.  H.,  0.86;  W.  K.,  0.82;  E.  D.  B.,  0.83;  and  for  the  three  members 
of  the  Laboratory  staff,  J.  H.  G.,  0.79;  E.  L.  F.,  0.85;  and  H.  M.  S., 
0.78.  Using  the  results  obtained  with  these  eight  subjects,  covering 
measurements  on  3  to  71  days,  and  in  most  instances  with  three 
periods  each  day,  we  may  conclude  that  the  average  respiratory  quo- 
tient of  a  normal  man  in  the  standing  position  and  the  post-absorptive 
condition  is  0.82.  This  value  is  slightly  lower  than  that  found  in 
measurements  made  (usually  on  other  days)  with  these  subjects  in  the 
lying  position,  both  for  the  average  value  as  well  as  in  all  but  one  of  the 
individual  cases  (see  table  17,  p.  91),  and  a  little  higher  than  the  respi- 
ratory quotient  obtained  at  the  Nutrition  Laboratory  with  normal 
men.3 

HEAT-OUTPUT. 

The  heat-output  of  these  standing  subjects,  as  calculated  from  the 
calorific  value  of  the  oxygen  consumed  and  the  respiratory  quotient,  is 
also  given  in  tables  3  to  7,  and  represents  the  energy  requirement  of  the 
subjects  when  standing  quietly  in  the  post-absorptive  condition.  This 
value  has  been  used  as  a  base-line  for  calculating  the  increase  in  the 
energy  requirement  due  to  the  muscular  effort  of  walking. 

The  values  of  W.  K.  show  considerable  daily  variation,  but  indicate 
no  regular  change.  With  E.  D.  B.  there  is  an  apparent  seasonal  change 
represented  by  the  periods  extending  from  October  4  to  December  22, 
1915,  when  the  total  heat-output  per  minute  was  1.10  calories,  and 
from  March  1  to  April  15,  1916,  when  the  average  was  1.18  calories. 

'Zuntz  and  Schumburg,  Physiologic  des  Marsches,  Berlin,  1901,  p.  259,  also  table  23,  p.  258. 

'Durig,  Archiv  f .  d.  ges.  Physiol.,  1906,  113,  p.  263. 

'Benedict,  Miles,  Roth,  and  Smith,  Carnegie  Inst.  Wash.  Pub.  No.  280,  1919,  p.  532. 


EXPERIMENTS   WITH   SUBJECT   STANDING. 


97 


During  this  time,  however,  E.  D.  B.  showed  a  gain  in  body-weight  of 
3.2  kg.  (see  table  21),  so  that  the  increase  in  the  heat-output  was  largely 
due  to  this  factor.  With  an  average  body-weight  of  56.2  kg.  during 
the  period  from  October  4  to  December  22,  1915,  his  metabolism  was 
28.2  calories  per  kilogram  of  body- weight  per  24  hours,  while  for  the 
period  from  March  1  to  April  15,  1916,  with  an  average  body-weight 
of  59.4  kg.,  his  metabolism  was  28.7  calories  per  kilogram  of  body- 
weight  per  24  hours.  When  the  data  for  the  eight  subjects  are  com- 
puted on  the  basis  of  body-weight,  they  show  an  average  energy 
requirement  per  minute  per  kilogram  of  body-weight  of  0.0197  calorie. 
(See  table  19.)  This  is  equivalent  to  1.18  calories  per  kilogram  per 
hour  as  compared  with  1.22  calories  per  kilogram  per  hour  reported  by 
Benedict,  Miles,  Roth,  and  Smith1  for  a  group  of  ten  normal  men  in 
standing  experiments. 

TABLE  19. — Average  heat-output  of  subjects  standing  in  the  post-absorptive  condition. 


Subject. 

No.  of 
days. 

Body-weight 
without 
clothing. 

Heat-output 
per 
minute. 

Heat-output  per  kg.  of 
body-weight. 

Per  min. 

Per  24  hrs. 

A.  J.  O  

3 
2 
3 
14 
71 
3 
3 
2 

kg. 
69.5 
70.0 
54.5 
49.2 
57.0 
70.4 
68.0 
60.4 

cals. 
1.31 
1.34 
1.11 
1.10 
1.16 
1.29 
1.34 
1.13 

cal. 
0.0188 
.0191 
.0204 
.0223 
.0203 
.0183 
.0197 
.0187 

cals. 
27.1 
27.5 
29.4 
32.1 
29.2 
26.4 
28.4 
26.9 

H.  R.  R  

T.  H.  H  

W.  K  

E.  D.  B  

E.  L.  F  

J.  H.  G  

H.  M.  S  

Average  

1.22 

.0197 

28.4 

GENERAL  SUMMARY  OF  MEASUREMENTS  OF  METABOLISM  DURING  STANDING. 

In  table  20  a  summary  is  given  of  the  extremes  and  average  values 
obtained  in  the  gaseous-metabolism  measurements  hi  the  standing 
experiments  with  W.  K.  and  E.  D.  B.,  with  whom  the  larger  part  of  the 
data  was  collected.  For  comparison,  average  values  and  ranges  are 
given  for  other  measurements  obtained  and  discussed  in  later  sections 
of  this  monograph.  (See  p.  101.)  These  figures  show  what  may  be  the 
ranges  and  average  values  for  the  various  factors  for  men  of  this  age 
when  they  are  standing  quietly  in  the  post-absorptive  condition.  The 
data  for  W.  K.  are,  for  the  most  part,  for  14  days,  covering  a  period  from 
February  to  June  1915,  and  for  E.  D.  B.  for  71  days  from  October 
1915  to  April  1916. 


'Benedict,  Miles,  Roth,  and  Smith,  Carnegie  Inst.  Wash.  Pub.  No.  280,  1919,  p.  528. 


98 


METABOLISM   DURING   WALKING. 


The  metabolism  measurements  for  E.  D.  B.  have  been  plotted  in 
figure  9,  which  shows  the  average  daily  values  on  the  dates  that  standing 
experiments  were  made  during  the  period  from  October  1915  to  April 
1916.  It  is  seen  from  this  chart  that  between  December  22  and  31, 
1915,  the  carbon-dioxide  output  and  oxygen  consumption,  as  well  as 
the  heat-output,  rose  to  a  markedly  higher  level,  the  values  being 
considerably  lower  between  October  and  December  than  those  obtained 
during  the  remainder  of  the  winter  and  in  the  spring  months.  This 
may  be  accounted  for  in  part  by  an  increase  in  the  body-weight  of 
approximately  7  per  cent,  but  this  alone  is  not  sufficient  to  account  for 
all  the  increase.  The  technique  of  the  experiments  had  not  been 
altered,  but  the  pulse-rate  showed  a  like  acceleration  at  this  time,  thus 
indicating  a  stimulated  body  condition  from  some  cause.  This  dif- 
ference in  the  metabolism  between  the  early  and  late  experiments  is 
shown  in  table  21,  in  which  the  averages  of  the  daily  values  for  the 
metabolism  from  October  4  to  December  22,  1915,  are  compared  with 
those  for  the  period  from  March  1  to  April  15,  1916.  These  values 
have  also  been  computed  on  the  basis  of  per  kilogram  of  body- weight, 
and  show  an  increase  in  the  total  heat  produced  per  kilogram  of  oody- 
weight  of  1.5  per  cent.  Since  only  the  increments  in  metabolism  are 


•c. 

37.39 


36.89 
36.39 


R.Q 
93 
83 
73 

O, 

o.  c. 
290 

240 
190 


FIG.  9. — Metabolism  of  E.  D.  B.  in  standing  experiments  without  food.    (Values  per  minute.) 


EXPERIMENTS   WITH   SUBJECT   STANDING. 


99 


considered  for  the  most  part  in  this  study  of  walking,  it  has  not  seemed 
necessary  to  duplicate  all  the  calculations  on  the  per  kilogram  of  body- 
weight  basis. 

TABLE  20. — Average  results  for  various  measurements  in  standing  experiments  with  W.  K. 

and  E.  D.  B. 


W.  K. 

E.  D.  B. 

Average. 

Range. 

Average. 

Range. 

Carbon  dioxide  c.  c. 
Oxygen  c.  c. 

186 

228 

174        to  200 
212        to  257 

199 
240 

181        to  225 

206        to  288 

Respiratory  quotient  

0.82 

0.74  to      0.91 

0.83 

0  74  to      0.93 

Heat-output  cala.  .  . 
Body-temperature  °C..  .  . 

1.10 

l.OSto      1.21 

1.16 
36  89 

1.01  to      1.36 
36  .  36  to    37  .  33 

Respiration-rate  

21.1 

18.1    to    24  9 

15  4 

12  3    to    16.7 

Pulmonary  ventilation  .  .  .  liters.  . 
Pulse-rate  

»6.45 
79 

5.  60  to     J7.4 
74        to    85 

9.1 

78 

6.2    to    10.1 
52        to    95 

Blood-pressure  mm.. 

116.5 

109        to  125 

'Does  not  include  March  18  and  June  2  to  14,  1915. 

TABLE  21. — Comparison  of  metabolism  of  E.  D.  B.  in  standing  experiments,  in  periods  Octo- 
ber 4  to  December  22,  1915,  and  March  1  to  April  15,  1916.     (Values  per  minute.) 


Oct.  4  to 

Mar.  1  to 

Measurement. 

Dec.  22, 

Apr.  15, 

1915. 

1916. 

Body-weight  without  clothing  

.kg..  .. 

56.2 

59.4 

Total  carbon  dioxide  

.c.  c.  .  . 

190 

201 

Total  oxygen  

.c.  c.  .  . 

226 

245 

Respiratory  quotient  

0.84 

0.82 

Total  heat  (computed)  

.  cals.  .  . 

1.10 

1.18 

Per  kilogrammeter  of  body-weight: 

Carbon  dioxide  

.c.  c...  . 

3.38 

3.38 

Oxygen  

.c.  c.  .  . 

4.02 

4.12 

Heat  per  minute  

.cals.  .  . 

0.0196 

0.0199 

Heat  per  hour  

.cals.  .  . 

1.176 

1.194 

Lusk1  reports  that  a  dog  which  had  been  allowed  to  run  in  the  country 
during  the  summer  months  showed  a  metabolism  16  per  cent  higher 
than  when  confined  in  the  laboratory.  Benedict,  Miles,  Roth,  and 
Smith2  also  noted  for  a  group  of  12  men  (Squad  B)  an  apparent  seasonal 
change  from  1.10  calories  to  0.98  calorie  per  kilogram  per  hour  in  the 
basal  metabolism  between  October  and  January.  A  seasonal  change 
in  the  metabolism  is  therefore  not  to  be  regarded  as  unusual,  and 
E.  D.  B.  may  have  found  the  regular  life  and  the  exercise  of  the  morning 


'Lusk,  Journ.  Biol.  Chem.,  1915,  20,  p.  564. 

'Benedict,  Miles,  Roth,  and  Smith,  Carnegie  Inst.  Wash.  Pub.  No.  280,  1919,  p.  523;  see, 
also,  footnote,  p.  500. 


100  METABOLISM   DURING  WALKING. 

walks  in  the  laboratory,  with  good  food  and  freedom  in  the  afternoon, 
of  such  benefit  that  it  resulted  not  only  in  an  increase  in  body-weight 
but  in  a  generally  improved  physical  condition. 

The  increase  in  the  pulse-rate  referred  to,  which  was  coincidental  with 
the  higher  level  of  the  heat-output,  is  readily  seen  in  figure  9,  in  which 
the  pulse-rate  is  plotted  for  43  days.  A  comparison  of  the  general 
trends  of  the  curves  for  pulse-rate  and  heat-output  shows  agreement,  the 
pulse  tending  to  increase  or  decrease  in  correspondence  with  the  heat. 
This  seems  to  confirm  the  statement  of  Benedict  and  Cathcart1  that 
for  the  same  individual  in  normal  health  and  hi  the  post-absorptive 
condition,  an  increased  metabolism  is  accompanied  by  an  increased 
pulse-rate.  There  is,  however,  a  marked  exception  to  this  agreement 
on  February  23,  when  the  heat-output  is  higher  than  that  of  the 
preceding  days  and  the  pulse-rate  shows  a  slight  fall.  As  was  stated  in 
discussing  the  oxygen  consumption  of  E.  D.  B.  for  this  day,  the  severest 
walking  test  for  this  subject  was  on  the  day  preceding  this  lowered 
pulse-rate.  During  this  test  his  oxygen  consumption  rose  to  3,132  c.  c. 
per  minute  and  he  was  exhausted  at  the  end  of  the  walking  periods.  It 
is  not  impossible  that  the  effect  upon  the  oxygen  consumption  was  also 
present  on  February  23,  whereas  the  pulse-rate  had  reached  a  more 
nearly  normal  basis. 

COMPARISON  OP  METABOLISM  FOR  LYING  AND  STANDING  POSITIONS. 

Strictly  speaking,  in  studying  the  effect  of  a  factor  showing  such  small 
differences  in  the  metabolism  as  is  produced  by  the  change  in  position 
from  standing  to  lying,  both  lying  and  standing  experiments  should  be 
made  on  the  same  day.  Since  this  difference  was  a  subsidiary  problem, 
and  the  time  could  not  be  spared  for  it  in  connection  with  the  walking 
tests,  we  must  use  average  values  for  comparison.  The  metabolism 
Qf  these  men  in  the  standing  position  may  be  compared  to  their  basal 
metabolism  recorded  for  the  lying  position  in  table  17,  page  91.  This 
comparison  has  been  made  in  table  22.  The  greatest  increase  in  the 
total  heat-output  due  to  the  change  in  position  is  found  with  W.  K. 
(21  per  cent)  and  the  smallest  increase  with  H.  R.  R.  (4  per  cent) .  The 
average  for  all  the  subjects  is  12  per  cent.  The  low  increase  for  H.  R.  R. 
can  hardly  be  attributed  to  his  basal  results,  for  they  represent  an 
average  of  32  experimental  periods  and  a  heat-output  per  kilogram 
of  body-weight  per  24  hours  of  26.6  calories,  which  is  of  the  same  order 
as  that  given  for  the  other  subjects  in  table  17;  nor  are  the  standing 
values  given  in  table  19  unduly  low,  for  the  average  total  heat-output 
of  H.  R.  R.  while  standing  is  1.34  calories  per  minute,  or  27.5  calories 
per  24  hours  per  kilogram  of  body-weight.  The  high  percentage 
increase  over  lying  of  W.  K.  is  due  to  his  relatively  high  standing  value, 

'Benedict  and  Cathcart,  Carnegie  Inst.  Wash.  Pub.  No.  187,  1913,  p.  154. 


EXPERIMENTS   WITH   SUBJECT   STANDING. 


101 


TABLE  22. — Comparison  of  the  total  metabolism  of  subjects  in  lying  and  standing  positions, 
with  percentage  increase  for  the  standing  position.     (Values  per  minute.) 


Subject. 

Carbon 
dioxide. 

Oxygen. 

Respiratory 
quotient. 

Heat-output. 

Increase  in 
standing 
over  lying. 

Ly- 
ing. 

Stand- 
ing. 

Ly- 
ing. 

Stand- 
ing. 

Ly- 
ing. 

Stand- 
ing. 

Ly- 
ing. 

Stand- 
ing. 

Oxy- 
gen. 

Heat. 

A.  J.  O  

c.  c. 
212 
215 
181 
159 
183 
204 
208 
172 

c.  c. 
226 
216 
196 
194 
199 
221 
224 
184 

c.  c. 
247 
269 
207 
187 
215 
247 
238 
196 

c.  c. 
271 
281 
227 
228 
240 
279 
265 
236 

0.86 
.80 
.87 
.85 
.85 
.83 
.87 
.88 

0.84 
.77 
.87 
.82 
.83 
.79 
.85 
.78 

cols. 
1.20 
1.29 
1.01 
.91 
1.05 
1.19 
1.16 
.96 

calx. 
1.31 
1.34 
1.11 
1.10 
1.16 
1.34 
1.29 
1.13 

p.  ct. 
10 
5 
10 
22 
12 
13 
11 
20 

p.  ct. 
9 
4 
10 
21 
11 
13 
11 
18 

H.  R.  R  

T.  H.  H  

W.  K  

E.  D.  B  

J.  H.  G  

E.  L.  F  

H.  M.  S  

Average  

192 

208 

226 

253 

.85 

.82 

1.10 

1.22 

13 

12 

which  is  1.10  calories  per  minute,  or  32.1  calories  per  24  hours  per  kilo- 
gram of  body-weight  (see  table  19)  rather  than  to  a  low  value  for  his 
metabolism  in  the  lying  position.  This  high  percentage  increase  finds 
support  in  the  value  of  18  per  cent  for  H.  M.  S.,  although  the  experi- 
ments with  this  subject  were  few  in  number,  being  only  one  for  the 
lying  position  and  two  for  the  standing.  The  results  in  table  22  would 
seem  to  indicate  that  the  effort  of  standing  was  marked  by  a  decided 
difference  in  the  energy  required  for  different  individuals,  with  an 
average  increase  of  10  to  12  per  cent. 

PHYSIOLOGICAL  EFFECTS  OF  STANDING. 

In  addition  to  measurements  of  the  metabolism  with  the  subjects 
standing,  records  were  also  obtained  of  the  respiration-rate,  pulmonary 
ventilation,  and  pulse-rate  by  the  methods  previously  outlined.  In 
many  of  the  experiments  with  E.  D.  B.,  records  were  also  obtained  of 
the  body-temperature  and  the  blood-pressure.  The  data  are  sum- 
marized in  table  23  and  given  in  detail  in  tables  3  to  7  (see  pp.  43  to  55). 

RESPIRATION-RATE  WITH  SUBJECT  STANDING. 

From  tables  3  and  23  it  is  seen  that  the  average  daily  respiration-rate 
for  A.  J.  0.  for  the  three  days  on  which  standing  experiments  were  made 
was  21.8,  but  there  are  too  few  experiments  to  give  evidence  of  any 
marked  change  in  this  factor.  That  the  respiration-rate  of  A.  J.  0., 
as  well  as  that  of  W.  K.,  is  higher  than  the  rates  of  the  other  subjects 
should  not  be  given  undue  weight. 

With  H.  R.  R.  the  respiration-rate  on  the  first  day  of  experimenting 
was  much  higher  than  on  subsequent  days,  the  average  for  the  day 


102 


METABOLISM   DURING   WALKING. 


TABLE  23. — Average  results  in  various  physiological  observations  with  subjects  standing. 

(Values  per  minute.) 


Subject. 

No.  of 
experi- 
ments. 

Respira- 
tion- 
rate. 

Ventila- 
tion of 
lungs. 

Pulse- 
rate. 

A.  J.  O  

3 

21.8 

liters. 
7.8 

H.  R.  R  

2 

15.5 

7.0 

93 

T.  H.  H  

3 

12.9 

6.5 

96 

W.  K.                

14 

21.1 

6.5 

79 

E.  D.  B1  

71 

15.4 

9.1 

78 

J.  H.  G  

3 

16.3 

10.6 

110 

E.  L.  F  

3 

15.0 

10.6 

107 

H.  M.  S  

2 

16.9 

10.0 

92 

'E.  D.  B.,  body-temperature  (40  days),  36.89°  C.;  blood-pressure  (20 
days),  116.5  mm. 

being  20.6.  (See  table  3,  p.  43.)  In  the  other  standing  experiments, 
the  respiration-rate  varied  from  14.9  to  16.6,  with  averages  on  April  10 
and  17,  1915,  of  approximately  15.5.  Undoubtedly  on  the  first  day 
(March  20)  the  subject  was  under  considerable  mental  excitement  and 
the  respiration-rate  recorded  for  this  day  was  probably  not  normal; 
it  has  therefore  been  omitted  hi  calculating  the  average.  The  data  in 
table  3  (p.  43)  give  no  marked  evidence  of  a  change  in  the  respiration- 
rate  in  any  one  direction  from  period  to  period  or  from  day  to  day, 
though  it  might  be  said  that  there  was  a  tendency  for  the  respiration- 
rate  to  be  lower  during  the  later  periods  of  the  day. 

The  respiration-rate  of  T.  H.  H.  shows  a  slight  tendency  to  increase 
from  period  to  period  on  the  days  when  standing  experiments  were 
made  with  this  subject.  The  daily  average  varied  from  12.7  to  13.2, 
with  a  general  average  of  12.9  for  the  series. 

The  average  respiration-rate  for  the  day  varied  with  W.  K.  from 
18.1  on  March  17  to  24.9  on  March  12,  1915,  with  an  average  for  the 
entire  series  of  21.1.  (See  table  5,  p.  44.)  There  was  no  marked  change 
one  way  or  the  other  in  the  rate  from  period  to  period  as  the  standing 
continued.  It  might  be  said  that  frequently  the'  highest  values  were 
obtained  during  the  first  period  of  the  several  experiments.  No 
tendency  is  shown  towards  a  decided  difference  in  the  respiration-rates 
obtained  hi  the  early  experiments  in  February  and  March  and  those 
recorded  in  the  later  experiments,  the  average  for  February  and  March 
being  21.1  and  that  for  May  and  June  21.2. 

E.  D.  B.  had  the  lowest  initial  daily  respiration-rate  of  any  of  the 
subjects.  His  average  rate  varied  from  12.3  on  October  4  (the  first 
record)  to  16.7  on  November  29,  1915.  An  inspection  of  table  6 
shows  that  there  is  a  slight  tendency  for  the  respiration-rate  to  increase 
in  the  succeeding  periods  of  the  forenoon.  This  increase  is  not  large 


EXPERIMENTS   WITH   SUBJECT   STANDING.  103 

and  but  rarely  amounts  to  a  full  respiration  per  minute.  There  are 
many  instances,  however,  in  which  the  rate  is  slower  in  the  latter  part 
of  the  forenoon.  With  this  subject  there  also  seems  to  be  an  increase 
in  the  respiration-rates  from  the  early  days  of  October  up  to  the  latter 
part  of  November.  Thus,  the  average  respiration-rate  for  the  seven 
days  from  October  4  to  14,  inclusive,  is  13.8,  and  the  average  rate  in 
the  standing  periods  from  November  18  to  December  22,  inclusive, 
is  15.1,  while  the  average  of  the  respiration-rates  between  April  8 
and  15,  inclusive,  is  15.4.  These  figures  show  that  there  was  un- 
doubtedly an  increase  in  the  rate  from  the  beginning  of  the  study  in 
October  up  to  the  latter  part  of  November,  while  but  little  change  took 
place  subsequent  to  that  time.  The  average  respiration-rate  for  the 
whole  series  with  E.  D.  B.  is  15.4. 

As  previously  stated,  during  the  period  that  E.  D.  B.  was  incapaci- 
tated on  account  of  his  lame  ankle,  three  of  the  assistants  served  as  vol- 
unteer subjects.  The  respiration-rates  obtained  with  J.  H.  G.,  E.  L.  F., 
and  H.  M.  S.  are  given  for  comparison  with  those  for  the  regular 
subjects.  There  is  considerable  difference  between  the  respiration- 
rate  of  E.  L.  F.  for  January  22  and  that  of  January  24,  1916.  This 
man  was  perfectly  familiar  with  the  routine  of  respiration  experiments 
as  carried  out  in  the  Nutrition  Laboratory,  although  January  21  was 
the  first  time  he  had  ever  been  the  subject  of  a  treadmill  experiment. 
The  protocol  for  January  24  notes  that  during  the  second  and  third 
standing  periods  he  showed  "considerable  fatigue"  at  the  end  of  each 
period  and  that  it  required  an  "effort  to  hold  out  to  the  end  of  the 
period."  The  statement  is  also  made:  "Subject  sweating  considerably 
at  the  end  of  the  period."  It  is  evident  that  this  man  was  not  in  the 
best  of  condition  on  that  day,  although  he  went  through  the  walking 
periods  subsequently  without  effort  or  complaint.  The  high  respira- 
tion-rate of  17.5  for  January  24  is  undoubtedly  due,  in  part  at  least, 
to  the  physical  condition  of  the  subject. 

PULMONARY  VENTILATION  WITH  SUBJECT  STANDING. 

The  data  showing  the  lung  ventilation  of  the  different  subjects  during 
the  standing  experiments  are  collected  in  tables  3  to  7  and  represent 
the  average  number  of  liters  of  air  entering  the  lungs  per  minute, 
reduced  to  standard  conditions  of  temperature  and  pressure,  i.  e., 
0°  C.  and  760  mm.  The  daily  averages  are  later  used  for  comparison 
with  the  increased  ventilation  requirements  during  walking.  The 
general  averages  for  the  subjects  are  summarized  in  table  23. 

A.  J.  O.  showed  a  ventilation  ranging  in  the  different  periods  from 
7.4  to  8.3  liters  per  minute,  with  an  average  value  of  7.8  liters  per 
minute  for  the  three  days  represented.  With  this  subject  there 
appeared  to  be  a  tendency  for  the  average  ventilation  to  increase 
from  day  to  day. 


104  METABOLISM   DURING   WALKING. 

With  H.  R.  R.  the  ventilation  per  minute  ranged  from  12.1  liters  for 
the  first  period  on  March  20  to  6.5  liters  for  the  third  period  on  April  17. 
The  average  for  the  day  ranged  from  11.7  liters  on  March  20  to  6.7  liters 
on  April  17.  This  wide  variation  is  undoubtedly  due  to  a  psychical 
disturbance  on  March  20,  when  H.  R.  R.  took  his  first  test.  Pulmonary 
ventilation  may  not  be  without  value  in  estimating  the  mental  re- 
pose of  a  subject.  In  this  connection  we  should  also  note  the  other  fac- 
tors measured,  such  as  pulses-rate  and  oxygen  consumption,  these  being 
higher  than  on  subsequent  days.  This  day's  results  have  been  excluded 
from  the  average,  although  there  is  every  reason  to  believe  that  they 
represent  the  pulmonary  ventilation  at  the  tune  of  the  experiment. 
The  average  ventilation  of  the  lungs  with  this  subject  for  the  entire 
series  of  experiments  is  8.5  liters  per  minute,  if  March  20  is  included, 
and  7.0  liters  without  this  day.  The  ventilation  in  the  first  period  of 
each  day  is  larger  than  the  subsequent  periods  and  the  daily  averages 
decreased  as  the  experimenting  continued. 

The  pulmonary  ventilation  of  T.  H.  H.  ranged  from  5.0  to  7.5  liters 
per  minute,  with  an  average  of  6.5  liters  per  minute  for  the  three  days. 
No  tendency  toward  a  uniform  change  in  the  ventilation  from  day  to 
day  or  from  period  to  period  is  apparent  and  his  ventilation  is,  on  the 
whole,  fairly  uniform. 

The  experiments  with  W.  K.  extended  from  February  to  June,  1915. 
The  lowest  pulmonary  ventilation  during  this  time  appeared  in  the 
first  period  on  March  11,  with  a  value  of  5.5  liters  per  minute,  and  the 
greatest  lung  ventilation  per  minute  was  in  the  second  period  on  both 
June  2  and  3,  i.  e.,  10.7  liters.  The  lowest  daily  average  was  5.7  liters 
on  March  17  and  the  greatest  10.6  liters  on  June  3.  When  we  examine 
this  series  of  figures,  it  is  noted  that  the  ventilation  on  March  18 
and  that  on  the  dates  subsequent  to  June  1  show  marked  increases. 
On  March  18  the  by-pass  (see  B,  fig.  1,  p.  19),  deflecting  the  circulating 
air-current  nearer  to  the  mouthpiece,  was  inadvertently  not  turned, 
thus  adding  somewhat  to  the  dead-space  of  the  apparatus.  It  is 
probably  due  to  this  fact  that  the  ventilation  was  increased  from  an 
average  of  5.7  liters  on  the  previous  day  to  9.0  liters  per  minute  on 
March  18.  The  by-pass  was  installed  in  anticipation  of  a  greater 
demand  for  ventilation  during  exercise  and  was  not  considered  so 
essential  for  the  standing  experiments.  As  further  evidence  of  the 
importance  of  its  use,  we  have  the  experiments  of  June  2  to  14,  in 
which  the  by-pass  was  purposely  not  used,  these  showing  that  the 
ventilation  of  the  lungs  is  again  very  much  higher.  The  average  ven- 
tilation of  the  lungs  of  6.5  liters  for  W.  K.  does  not,  therefore,  include 
the  data  for  March  18  and  the  observations  from  June  2  to  June  14, 
when  the  by-pass  was  not  used.  If  we  omit  these  days  from  the  dis- 
cussion, we  find  that  the  daily  average  ventilation  of  W.  K.  ranged 
from  5.7  liters  (the  average  for  March  17)  to  7.4  liters  (the  average  for 


EXPERIMENTS   WITH    SUBJECT    STANDING. 


105 


March  13),  with  no  tendency  for  the  ventilation  to  change  hi  any  one 
direction  as  the  season  advanced  hi  the  period  from  February  26  to 
June  1.  During  this  time  the  man  was  walking  almost  daily  on  the 
treadmill  at  considerable  grades  and  speeds.  On  many  days  the  ven- 
tilation in  the  first  period  of  the  day  was  greater  than  that  hi  succeed- 
ing periods,  but  there  are  a  sufficient  number  of  exceptions  to  prevent 
the  making  of  any  categorical  statement. 

E.  D.  B.  has  the  largest  number  of  periods  and  days  from  which 
comparisons  may  be  made.  The  pulmonary  ventilation  varied  with 
this  subject  from  6.1  liters  per  minute  hi  the  first  periods  of  November 
18  and  19  to  10.3  liters  per  minute  hi  the  third  period  of  December  31, 
while  the  daily  average  varied  from  6.2  liters  per  minute  on  November 
18  to  10.1  liters  per  minute  on  February  15.  The  figure  for  February 
15  was,  however,  the  record  of  but  one  period.  The  low  averages  of  6.2 
liters  for  November  18  and  of  6.3  liters  on  the  day  following  are 
exceptional,  as  aside  from  these  two  days  the  lowest  daily  average  is  8.0 
liters  on  December  22.  The  figures  for  the  lung  ventilation  on  Novem- 
ber 18  and  19  are,  however,  believed  to  be  correct,  as  the  tracings  on 
the  kymograph  have  beeji  measured  and  agree  with  the  record  of  the 
ventilation  adder.  They  are  accordingly  included  in  the  general  aver- 
age for  the  lung  ventilation  of  E.  D.  B.,  which  is  9.1  liters  per  minute. 

The  data  for  the  ventilation  of  the  lungs  do  not  indicate  that  it  was 
larger  at  any  particular  period  of  the  day  than  at  another.  Though 
there  are  variations,  they  are  no  greater  than  might  be  expected  and 
appear  to  be  as  much  in  one  direction  as  in  the  other.  On  the  whole, 
the  ventilation  seems  to  be  fairly  uniform  for  each  day's  series.  If  the 
daily  average  ventilation  is  compared  by  periods  of  10  days  or  2  weeks 
we  have  the  following  results  for  liters  per  minute: 


Oct.  4 
to  14. 

Oct.  15 
to  29. 

Nov.  27 
to  Dec.  22. 

Mar.  1 
to  31. 

Apr.  1 
to  15. 

8.6 

9.3 

9.0 

9.2 

9.2 

The  two  exceptionally  low  values  obtained  on  November  18  and  19, 
1915,  were  omitted  from  these  averages.  It  would  appear  from  this 
grouping  of  the  values  that  after  the  first  10  days  the  lung  ventilation 
of  the  subject  while  standing  did  not  materially  alter  as  a  result  of  his 
daily  exercise  in  walking. 

The  lung  ventilation  of  J.  H.  G.  showed  an  increase  for  each  suc- 
ceeding period  on  the  three  days  that  he  was  a  subject,  with  a  variation 
in  the  daily  average  from  10.1  to  11.3  liters  per  minute  and  an  average 
for  the  three  days  of  10.6  liters  per  minute.  With  E.  L.  F.  the  venti- 
lation increased  considerably  on  January  24  over  that  of  the  preceding 
days,  the  pulse-rate  also  showing  an  increase  on  that  day;  but  this  high 


106 


METABOLISM   DURING   WALKING. 


value  is  included  in  the  total  average  of  10.6  liters  per  minute  for  this 
subject.  In  the  two  days  that  H.  M.  S.  served  as  subject,  the  ventila- 
tion varied  from  9.9  to  10.3  liters  per  minute,  with  an  average  of  10 
liters  per  minute. 

In  looking  over  the  figures  for  pulmonary  ventilation,  it  is  evident 
that  there  is  a  possibility  of  considerable  variation  in  this  factor,  not 
only  from  day  to  day  but  from  period  to  period.  This  variation  makes 
it  difficult  to  state  definitely  whether  or  not  training  on  the  apparatus 
has  any  influence  in  the  volume  of  air  inhaled  into  the  lungs.  The 
most  definite  information  on  this  point  is  found  with  E.  D.  B.,  with 
whom  during  the  second  fortnight  there  was  an  average  increase  of  0.7 
liter  over  the  ventilation  in  the  preceding  10  days,  while  for  the  re- 
mainder of  the  season,  a  period  of  approximately  6  months,  the  dif- 
ference was  not  more  than  0.3  liter.  The  fact  that  the  use  of  the  by- 
pass was  omitted  in  the  later  standing  experiments  with  W.  K.  prevents 
any  definite  conclusion  on  this  point  from  his  data,  while  the  experiments 
with  the  other  subjects  were  too  few  to  throw  light  on  the  point  under 
discussion. 

When  the  average  pulmonary  ventilation  per  minute  of  these  men  is 
compared  on  the  basis  of  nude  weight,  it  is  found  that  the  ventilation 
of  the  lungs  is  not  directly  conditioned  by  this  factor.  That  a  con- 
siderable variation  in  the  ventilation  per  kilogram  of  body-weight  is 
possible  is  seen  by  the  comparison  made  in  table  24.  Subsequent 
research  must  take  into  consideration  vital  capacity1  as  well  as 
pulmonary  ventilation. 

TABLE  24. — Average  lung  ventilation  per  kilogram  of  body-weight  with  subject  standing. 

(Values  per  minute.) 


Subject. 

Body-weight 
without 
clothing. 

Pulmonary 
ventilation 
(reduced). 

Ventilation 
per 
kilogram  of 
body-weight. 

A.  J.  O  

kg. 
69.5 

liters. 
7.8 

liter. 
0.112 

H.  R.  R  

70  0 

7.0 

.100 

T.  H.  H  

54  5 

6.5 

.119 

W.  K  

49.2 

6.5 

.132 

E.  D.  B  

57.0 

9.1 

.160 

J.  H.  G  

68.0 

10.6 

.156 

E.  L.  F  

70.4 

10.6 

.151 

H.  M.  S  

60.4 

10.0 

.166 

PULSE-RATE  WITH  SUBJECT  STANDING. 

The  oscillograph  for  securing  electro-cardiograms  was  not  in  a  satis- 
factory working  condition  until  the  middle  of  March  1915,  and  the 

Greyer,  Lancet,  1919,  197,  p.  227;  ibid.,  1920,  199,  p.  289.  Dreyer  and  Hanson,  The  assess- 
ment of  physical  fitness  by  correlation  of  vital  capacity  and  certain  measurements  of  the 
body,  London,  1920. 


EXPERIMENTS   WITH   SUBJECT   STANDING.  107 

making  of  a  few  adjustments  prevented  further  records  for  nearly  a 
week.  On  this  account,  no  pulse  measurements  were  made  for  A.  J.  O. 
and  the  records  are  incomplete  for  T.  H.  H.  and  W.  K.  As  explained  in 
an  earlier  section  (see  p.  34),  the  difficulties  experienced  in  the  use  of  the 
oscillograph  were  so  many  that  the  string  galvanometer  was  substituted 
in  the  early  whiter  of  1915,  and  subsequently  used  for  measuring  the 
pulse-rates  of  E.  D.  B.,  E.  L.  F.,  J.  H.  G.,  and  H.  M.  S.  The  data 
obtained  are  recorded  and  averaged  in  tables  3  to  7.  (See  pp.  43  to  55.) 

It  is  a  recognized  fact  that  the  pulse-rate  is  liable  to  sudden  and  un- 
expected changes,  even  when  the  subject  is  at  complete  rest,1  and  that 
the  rate  may  be  stimulated  by  thought  or  anticipation.2  It  is,  there- 
fore, with  considerable  hesitation  that  the  term  "average  standing 
pulse-rate"  is  used.  It  is  necessary,  however,  to  have  some  basis  to 
work  from  and  the  term  as  here  employed  represents  the  general  aver- 
age of  the  records  of  each  day  for  the  individual  subjects,  regardless  of 
whether  they  include  one  or  more  periods.  For  instance,  with  W.  K. 
on  March  16,  the  daily  average  of  81  is  obtained  from  the  record  for  the 
first  period  only3  and  on  June  4  the  rate  of  74  is  from  the  third  period 
only,  while  that  of  85  for  June  1  is  the  average  for  four  standing  periods 
on  that  day.  (See  table  5,  p.  44.)  It  may  be  justly  said  that  the  rates 
of  81  and  74  for  March  16  and  June  4  are  given  too  much  weight  by  this 
method  of  averaging,  but  it  has  not  seemed  necessary  to  undertake  a 
more  complicated  method,  as  such  a  change  would  not  affect  materially 
the  general  picture  of  the  variations  hi  pulse-rate.  This  is  especially 
true  in  view  of  the  fact  that  on  the  days  when  both  standing  and  walking 
experiments  were  made,  the  standing  rate  for  the  day,  and  not  the  aver- 
age rate  for  all  the  standing  experiments  with  that  subject,  has  been 
used  as  the  base-line  in  determining  the  change  in  the  pulse-rate  during 
the  subsequent  periods  of  walking  on  that  particular  day. 

With  these  statements  in  mind,  it  is  seen  from  table  4,  page  44,  that 
T.  H.  H.  had  an  average  pulse-rate  on  March  19  of  100,  with  variations 
on  this  date  from  97  in  the  first  period  to  103  in  the  third.  Three  days 
later  (March  22)  the  average  rate  was  91,  with  a  range  from  87  in  the 
first  period  to  96  in  the  last  period.  The  average  for  the  two  days  was 
96.  On-  both  days  the  pulse-rate  increased  during  each  succeeding 
period,  indicating  that  the  effort  of  continuous  standing  increased  the 
work  of  the  heart. 

The  first  day  on  which  H.  R.  R.  was  a  regular  subject  (March  20), 
he  had  an  average  pulse-rate  of  108.  (See  table  3.)  While  his  pulse- 
rate  was  probably  stimulated  on  this  day,  owing  to  the  novelty  of  the 

Benedict,  Miles,  Roth,  and  Smith,  Carnegie  Inst.  Wash.  Pub.  No.  280,  1919,  p.  389. 

2Favill  and  White,  Heart,  1917,  6,  p.  175;  also,  West  and  Savage,  Arch.  Intern.  Med.,  1918, 
22,  p.  290. 

3It  should  be  emphasized  that  all  counts  were  made  photographically  and  several  exposures 
were  secured  during  each  period.  The  average  for  each  period  thus  represents  almost  invariably 
not  less  than  three  separate  counts. 


108  METABOLISM   DURING   WALKING. 

experience,  the  average  rates  of  95  and  91  obtained  on  the  other  two 
days  indicate  that  the  subject  had  a  normally  high  pulse-rate  for  the 
standing  position.  It  was  also  noted  that  the  pulse-rate  of  this  subject 
while  he  was  in  the  lying  position  was  much  higher  than  that  of  the  other 
subjects.  (See  table  17,  p.  91.)  The  average  rate  for  three  days  of 
experimenting  with  him  was  98.  Excluding  the  high  pulse-rate  of  the 
first  day,  it  was  93.  The  change  hi  the  rate  during  the  succeeding 
periods  of  the  day  is,  on  the  whole,  the  reverse  of  that  shown  by  T.  H.  H. 
and  indicates  that  the  psychical  effect  passed  away  more  rapidly  than 
the  physical  effort  of  standing  increased  the  heart-rate,  if,  indeed,  there 
were  such  an  effect.  This  may  be  questioned  in  view  of  the  decrease 
in  the  pulse-rate.  H.  R.  R.  was  of  a  nervous  type,  while  T.  H.  H. 
was  phlegmatic. 

The  first  record  with  W.  K.  was  made  on  March  11,  1915,  when  an 
average  pulse-rate  of  79  was  obtained.  This  man  had  acted  as  subject 
for  several  days  previous  to  this  date.  Consequently,  if  there  had 
been  any  unusual  stimulation  on  earlier  days  due  to  the  novelty  of  the 
test,  it  had  all  disappeared  when  the  first  pulse-record  was  made, 
since  the  subsequent  measurements  with  the  subject  standing,  even 
to  the  close  of  experimenting  with  this  subject  in  June,  1915,  approxi- 
mated this  figure.  This  approximate  uniformity  may  be  seen  by  the 
detailed  pulse-rate  records  given  for  W.  K.  in  table  27,  page  111. 
From  table  5,  we  see  that  the  highest  period  rate  found  during  the 
standing  experiments  was  87  in  the  first  period  on  March  17  and  the 
fourth  period  of  June  1 ;  the  lowest  value  was  73  in  the  second  period 
on  May  29.  The  daily  average  varied  from  74  on  May  29  and  June 
4  to  85  on  June  1.  There  is  no  clear-cut  evidence  that  the  pulse-rate 
increased  as  the  standing  continued.  On  Mar-ch  17  it  tended  to  fall ; 
on  March  18  it  had  a  tendency  to  increase;  on  the  other  days  the 
changes  were  irregular  and  insignificant.  The  average  standing  pulse 
for  this  subject  was  79  beats. 

Owing  to  our  difficulties  with  the  oscillograph,  records  were  not 
obtained  with  E.  D.  B.  until  November  29, 1915.  At  that  tune  he  had 
become  fairly  accustomed  to  the  conditions,  so  that  the  novelty  of  the 
exercise  played  no  r61e.  The  illustrative  pulse-records  in  figure  8 
(p.  34)  are  all  for  this  man.  Electro-cardiograms  wete  obtained  with 
E.  D.  B.,  standing,  on  43  days.  (See  fig.  9,  p.  98,  and  table  6,  p.  46.) 
These  records  show  pulse-rates  ranging  from  52  on  February  19  to  96 
in  the  first  period  on  February  1.  The  low  rate  of  February  19  is  the 
average  of  three  1-minute  records,  taken  four  minutes  apart,  of  50, 
52,  and  53.  It  seems  evident,  therefore,  that  the  value  of  52  correctly 
represents  the  average  standing  pulse  for  this  day  and  that  the  rate 
was  lower  on  this  date  than  on  others.  This  is  the  lowest  average 
pulse-rate  of  a  man  standing  that  we  have  observed,  save  in  the  case 
of  a  few  subjects  on  prolonged  low  diet.1  The  high  rate  of  96  in  the 

Benedict,  Milea,  Roth,  and  Smith,  Carnegie  Inat.  Wash.  Pub.  No.  280,  1919,  p.  413. 


EXPERIMENTS   WITH    SUBJECT    STANDING. 


109 


first  period  of  February  1  is  likewise  the  average  of  three  counts  of 
from  44  to  61  seconds,  giving  pulse-rates  of  95,  93,  and  99.  These 
high  figures  and  the  high  average  for  this  day  and  for  the  day 
preceding  may  find  some  explanation  in  the  fact  that  E.  D.  B.  had  not 
acted  as  subject  for  three  weeks  prior  to  January  31,  owing  to  lameness 
(see  p.  42).  Accordingly  an  element  of  excitement  may  have  been 
introduced  by  the  fact  that  he  was  resuming  the  experiments.  Fur- 
thermore, a  note  in  the  protocol  for  January  31  says  "slight  cold  and 
hoarseness,"  and  on  February  1  the  note  is  made  that  the  "subject 
seemed  to  have  a  slight  cold  in  the  throat."  It  is  possible,  therefore, 
that  the  pulse-rate  for  these  two  days  should  not  be  included  in  the 
daily  averages,  although  this  has  been  done  in  computing  the  general 
average  of  78  for  this  subject.  If  these  are  excluded,  the  average 
standing  pulse-rate  for  E.  D.  B.  is  77,  a  difference  which  is  negligible. 
The  few  pulse-rates  obtained  with  the  laboratory  assistants  and 
recorded  in  table  7  (p.  55)  give  but  little  idea  of  the  true  pulse-rate 
during  standing,  as  they  are  apparently  influenced  by  other  factors. 
The  records  for  J.  H.  G.  show  a  daily  pulse-rate  varying  from  117 
to  106.  He  found  standing  very  irksome  on  January  18  and  reported 
that  his  knees  were  "shaky"  at  the  close  of  the  standing  experiment. 
He  made  no  such  comment  on  the  other  days.  The  pulse-rate  of 
E.  L.  F.  on  January  21  showed  a  rapid  increase  during  the  first  period 
as  the  experiment  continued,  rising  from  87  after  one  minute  of  stand- 
ing to  95  and  108  at  intervals  of  5  and  4  minutes,  respectively.  The 
other  two  standing  periods  on  this  date  showed  some  increase,  but 
not  so  large  as  this.  On  January  24  the  statement  is  made  in  the 
protocols:  "Subject  all  tired  out  at  end  of  third  period;  complained  of 
headache."  He  was  apparently  not  in  the  best  of  physical  condition 
on  this  day,  but  continued  with  the  morning  routine,  three  walking 
periods  following  the  standing  periods.  H.  M.  S.  on  January  25 
"found  standing  tiresome"  and  "was  glad  to  start  walking."  The 
records  for  each  period  are  unusually  uniform.  As  evidence  that  the 
variations  met  with  in  the  course  of  this  study  are  due  to  the  personal 
element  and  not  to  the  technique,  the  records  of  H.  M.  S.  are  given  in 
detail  in  table  25.  It  may  be  said  that  the  age  of  this  subject  and  his 

TABLE  25. — Detailed  pulse-rate  records  for  H.  M.  S.,  standing. 


Date  and 
period. 

First 
record. 

Second 
record. 

Third 
record. 

1916. 
January  25: 
First  

96.7 

97.7 

Second  

96  0 

98.1 

97  6 

Third  

95.4 

100.9 

January  26: 
First  

85.2 

88.8 

85.3 

Second  

86.1 

88.8 

Third  .  . 

87.6 

85.5 

85.6 

110 


METABOLISM   DURING   WALKING. 


greater  familiarity  with  the  experimental  technique  resulted  in  a  more 
nearly  uniform  pulse-rate,  but  evidently  these  factors  did  not  prevent 
a  stimulated  pulse-rate  on  the  first  experimental  day. 

During  the  time  of  this  study  most  of  these  men  had  also  served  as 
subjects  in  other  respiration  experiments  in  the  Nutrition  Laboratory. 
In  these  cases  the  men  were  lying  quietly,  and  we  thus  have  evidence 
as  to  the  pulse-rates  of  the  individual  subjects  under  such  conditions 
The  average  results  for  four  men  with  whom  the  pulse-rate  was 
counted  with  a  stethoscope  have  been  averaged  and  are  given  in 
table  26,  in  which  they  are  compared  with  the  average  pulse-rates 

TABLE  26. — Comparison  of  the  average  pulse-rates  of  four  subjects  for  the  lying  and  standing 

positions.     (Values  per  minute.) 


Subject. 

No.  of  experimental 
periods. 

Pulse-rate. 

Lying 
position. 

Standing 
position. 

Lying 
position. 

Standing 
position. 

Increase 
for 
standing 
over  lying. 

Per- 
centage 
increase. 

H.  R.  R  

32 
64 

128 
10 

8 
5 
25 
105 

73 
59 

57 
58 

93 
96 

79 

78 

20 
37 
22 
20 

27 
63 
39 
34 

T.  H.  H  

W.  K  

E.  D.  B  

Average  

62 

87 

25 

41 

Squad    A1    (av.    11 
men,  reduced  diet) 
Squad    B1    (av.     11 
men,  normal  diet.) 

45 
56 

64 
76 

17 

18 

38 
32 

Benedict,  Miles,  Roth,  and  Smith,  Carnegie  Inst.  Wash.  Pub.  No.  280,  1919,  table  93,  p.  413. 

obtained  photographically  for  the  same  subjects  in  the  standing  posi- 
tion. The  number  of  experimental  periods  in  which  records  of  the 
pulse-rate  were  obtained  ranged  for  the  lying  position  from  10  periods 
with  E.  D.  B.  to  128  periods  with  W.  K.,  and  for  the  standing  position 
from  5  periods  with  T.  H.  H.  to  105  periods  with  E.  D.  B. 

The  pulse-rate  for  the  lying  position  is  considerably  higher  for 
H.  R.  R.  than  for  the  others,  confirming  our  impression  of  him  as  of  a 
nervous  temperament,  and  accounting  in  some  degree  for  the  high 
pulse-rate  found  for  the  standing  position.  With  so  high  a  pulse-rate 
for  the  basal  value,  the  percentage  increase  for  the  standing  position 
with  H.  R.  R.  is  below  the  average,  being  27  per  cent.  The  reverse  is 
true  with  T.  H.  H.  In  his  case  the  influence  of  novelty  in  the  standing 
experiment  resulted  hi  a  pulse-rate  of  96,  which  is  probably  abnormally 
high.  This  is  the  average  of  two  days'  records  with  five  experimental 
periods,  the  pulse-rate  on  the  first  day  averaging  100  and  on  the  second 


EXPERIMENTS   WITH    SUBJECT   STANDING. 


Ill 


day  91  beats  per  minute.  With  the  other  two  subjects  the  data  are 
sufficient  to  give  a  picture  which  is  probably  truer  than  that  of  T.  H.  H., 
these  showing  a  percentage  increase  of  34  to  39  per  cent  for  standing  as 
compared  with  the  rates  found  for  the  lying  position. 

In  a  publication  recently  issued  from  the  Nutrition  Laboratory,1 
some  data  were  given  on  the  change  in  the  pulse-rate  with  two  groups 
of  11  men  each,  one  of  these  groups  (Squad  A)  being  on  a  reduced  diet 
with  a  very  much  lowered  basal  metabolism,  and  the  other  (Squad  B) 
on  a  normal  diet.  From  the  figures  in  table  26,  it  is  seen  that  the  pulse- 
rate  of  Squad  A  on  a  reduced  diet  increased  38  per  cent  for  the  standing 
position  as  compared  with  that  found  when  the  men  were  lying  down. 
With  the  men  in  Squad  B  on  normal  diet,  the  pulse-rate  for  the  standing 
position  showed  an  increase  of  32  per  cent.  These  figures  agree  with 
those  reported  for  the  subjects  of  the  present  research.  From  the  above 
comparison  it  may  be  said  that  the  work  of  standing  increases  the 
pulse-rate  approximately  35  per  cent  over  that  for  the  lying  position. 

TABLE  27. — Detailed  pulse  records  of  W.  K.  during  standing  and  walking  experiments  without 

food.     (Values  per  minute.) 


Date. 

Conditions. 

Period. 

Pulse-rate  during  period 
at  approximately  — 

Average 
pulse- 
rate  for 
period. 

2  min. 

6  min. 

10  min. 

1915 
Mar.  11 

Mar.  16 
Mar.  17 

Standing  

Prelim  
1 
2 
Interval 

81 

172 

77 
78 
80 
72 
78 
81 
74 
77 
78 
78 
81 
87 
82 
77 
75 
73 
77 
84 

Do  

78 

Do  

82 

78 

Do  

Do  

3 
1 
4 
5 
6 
7 
Prelim  
1 
2 
3 
4 
5 
6 
Final     

78 
78 

77 
84 
73 
75 
80 
78 

79 
82 
74 

79 
77 
77 
78 
90 
82 
78 
77 

Do  

Walking  level  

Do  

79 
76 

Do  

Do  

Standing  

83 
83 

81 
75 
73 
73 

Do  

87 
83 
77 
75 

Do  

Do  

Walking  level  

Do. 

Do  

77 

Standing  

84 

'After  25  minutes  of  standing. 

To  note  the  changes  in  pulse-rate  within  the  period,  detailed  data 
for  the  standing  experiments  of  W.  K.  have  been  collected  in  table  27. 
The  records  were  usually  made  at  the  second,  sixth,  and  tenth  minutes 
of  the  period.  The  pulse-rates  obtained  in  the  walking  experiments  on 
the  same  dates  are  also  included.  Table  27  likewise  shows  a  few  rates 
which  were  determined  preliminary  to  the  periods,  in  intervals  between 
periods,  and  when  the  subject  was  standing  after  walking. 

Benedict,  Miles,  Roth,  and  Smith,  Carnegie  Inst.  Wash.  Pub.  No.  280,  1919,  p.  413,  table  93. 


112 


METABOLISM   DURING  WALKING. 


TABLE  27. — Detailed  pulse  records  of  W.  K.  during  standing  and  walking  experiments  without 
food.     (Values  per  minute.) — Continued. 


Date. 

Conditions. 

Period. 

Pulse-rate  during  period 
at  approximately  —  . 

Average 
pulse- 
rate  for 
period. 

2  min. 

6  min. 

10  min. 

1915. 

May  18 

29 
June    1 
2 
3 

4 
14 

Standing  

Prelim  

J81 
77 
79 
84 
72 
76 
74 
76 
76 

»74 
83 
81 
83 
74 
79 
73 
77 
82 

78 
80 
81 
84 
73 
77 
74 
77 
78 
71 
72 
75 
73 
74 
135 
146 
149 
113 
86 
85 
81 
87 
148 
155 
160 
»126 
76 
81 
78 
67 
140 
147 
151 
123 
74 
79 
78 
79 
74 
74 
76 
79 
69 
74 
74 
74 
77 
75 
67 
83 
78 
74 
158 
169 
174 
147 

Do  

1 
2 
3 
Prelim  
4 
5 
6 
7 
Final  

81 
83 
86 

Do  

Do  

Walking  level  

Do  

77 
74 

Do  

Do  

Do  

78 

Standing  

Do  

Prelim  

Do  

1 
2 
3 
4 
5 
6 
Final   

71 
72 
71 
133 

75 
74 
74 
136 
146 
150 
109 
88 
82 
82 
89 
150 
156 
162 
119 

78 
73 
77 
137 
147 
151 
106 
88 
88 
84 
87 
152 

Do  

Do  

Walking  grade,  15.3  p.  ct  

Do  

Do.  ... 

147 
124 
82 
84 
79 
85 
142 
155 
157 
145 

Standing  

Do  

1 
2 
3 
4 
5 
6 
7 
Final 

Do  

Do  

Do  

Walking  grade,  15.3  p.  ct  

Do  

Do  

161 
126 

Standing  

Do  

Prelim. 

Do  

1 
2 
Interval   . 

78 
74 

82 

77 

85 
83 

Do  

Do  

Walking  grade,  15.3  p.  ct  

4 
5 
6 
Final  
Prelim   . 

137    - 
143 
149 
127 

139 
149 
151 
119 

145 
149 
153 

Do  

Do  

Standing  .    . 

Do  

Do  

1 
2 
3 

4 
5 
6 
7 
Final  
3 
4 
5 
6 
7 
Final  
Prelim.  .  .  . 

76 
74 
79 

79 

78 
77 
73 
73 
77 
78 
65 
74 
76 
74 
77 
75 
68 

83 
83 
80 

75 
74 
77 
79 

Do  

Do  

Marking  time  ....        

Do  

74 
73 
79 
72 
68 
72 
72 
77 
73 
67 

Do  

Do  

Standing.  .  . 

Do  

78 
74 
75 
76 
76 

Marking  time  

Do  

Do  

Do  

Standing  

Do  

Do  ;.. 

1 
3 
4 
5 
6 
Final  

76 
72 
158 
169 
173 
137 

79 
76 
161 
171 
174 

Do  

74 
155 
166 

Walking  grade,  20.0  p.  ct  
Do  

Do  

Standing  

157 

1  After  16  minutes  of  standing. 
*  After  12  minutes  of  standing. 


'15  minutes  after  end  of  period,  pulse-rate  115. 


EXPERIMENTS   WITH   SUBJECT   STANDING.  113 

An  examination  of  the  pulse-records  for  W.  K.  in  the  standing 
position  show  that,  on  the  whole,  the  rate  changed  during  the  period 
toward  a  slightly  higher  level  as  the  standing  continued,  this  change 
being  with  few  exceptions  between  2  and  4  beats.  The  interval 
between  periods  was  usually  sufficient  to  bring  the  pulse-rate  to  the 
original  daily  level,  as  seen  by  a  comparison  of  the  first  records  obtained 
in  each  period.  An  exception  is  found  to  this  on  March  18.  This 
increase  in  the  pulse-rate  during  the  standing  period  and  the  decrease 
during  the  interval  between  periods,  notwithstanding  the  fact  that  the 
subject  was  standing  in  both  cases,  is  probably  due  to  the  undoubted 
effort  during  the  periods  of  measurement  of  standing  motionless  with- 
out any  relaxation  by  change  of  position.  Although  the  subject  did 
not  keep  his  muscles  rigid  during  these  periods,  he  neither  moved  his 
arms  nor  shifted  his  weight  from  one  leg  to  the  other.  Furthermore, 
there  was  probably  the  added  effect  of  consciousness  of  the  progress  of 
the  experiment  which  tended  to  act  as  a  psychical  stimulus  to  the 
pulse-rate.  It  may  likewise  be  noted  from  table  27,  although  the  point 
will  be  referred  to  again  (see  p.  165),  that  the  average  pulse-rate  of  this 
subject  in  level  walking  was  lower  in  several  instances  than  the  average 
of  the  preceding  standing  periods. 

RECTAL  BODY-TEMPERATURE  WITH  SUBJECT  STANDING. 

Relatively  few  observations  were  made  of  the  body-temperature, 
and  these  were  with  but  one  subject  (E.  D.  B.) .  Obviously,  the  prin- 
cipal interest  of  these  observations  is  in  indicating  the  influence  of  the 
work  of  walking.  The  averages  of  the  records  for  the  standing  periods 
are  given  in  table  6a,  and  are  shown  graphically  in  figure  9.  In  a  few 
instances  they  represent  but  two  readings  taken  at  the  beginning  and 
end  of  the  periods,  respectively,  but  in  the  majority  of  cases  the  average 
is  for  some  5  to  7  readings,  made  at  regular  intervals  during  the  period. 

The  daily  average  rectal  temperature  with  this  subject  standing 
ranges  from  36.36°  C.  on  February  19  to  37.25°  C.  on  February  1  and 
23,  and  37.33°  C.  on  March  24,  i.  e.,  well  within  "normal"  limits.  The 
temperature  of  36.36°  C.  on  February  19  is  for  one  period  only,  but  is 
an  average  of  5  readings  which  show  no  greater  deviation  than  on  other 
days  and  the  resistance  thermometer  had  been  worn  by  the  subject  21 
minutes  before  the  first  reading  was  taken;  there  seems  to  be  no  reason, 
therefore,  for  doubting  the  reliability  of  this  value.  In  connection 
with  the  high  value  for  February  23  (37.25°  C.),  the  experimental  sheet 
carries  this  notation:  "Difficult  to  get  good  balance  during  the  first 
period."  "At  end  of  third  period,  the  galvanometer  deflected  with  each 
step."  "Thermometer  check  in  afternoon  found  O.  K."  Apparently 
on  this  date  there  was  some  trouble  with  the  insertion  of  the  thermom- 
eter and  the  temperature  as  recorded  is  liable  to  contain  some  error. 
On  February  1,  when  the  body-temperature  was  also  37.25°  C.,  the 


114  METABOLISM   DURING   WALKING. 

records  state  that  the  subject  seemed  to  have  a  slight  cold  on  this  day, 
as  well  as  on  the  day  before.  The  temperature  on  January  31  was  also 
high.  The  value  for  March  24  (37.33°  C.)  is  the  average  for  three 
periods,  with  all  of  the  records  relatively  high,  especially  that  for 
the  first  period.  No  comment  appears  on  the  experimental  sheet  for 
the  day  other  than  the  statement  twice  made  of  "leads  balanced." 
The  general  average  rectal  temperature  with  the  subject  standing 
shown  for  these  40  days,  i.  e.,  January  5  to  April  15,  1916,  is  36.89°  C. 
In  subsequent  sections,  in  comparing  the  changes  in  the  body- 
temperature  during  walking,  the  general  average  temperature  obtained 
with  the  subject  standing  has  been  used  as  a  base-line  for  those  days 
when  no  standing  experiments  were  carried  out.  Though  this  method 
is  not  so  exact  as  a  comparison  with  a  standing  base-line  obtained  on 
the  individual  days,  it  is  probably  within  the  limits  of  error  of  any 
method  employed  for  obtaining  an  accurate  measure  of  the  tempera- 
ture of  the  body-mass.  Benedict,  Miles,  and  Johnson1  have  shown 
that  there  is  a  wide  variation  in  the  surface-temperature  of  the  body 
and  that  proximity  to  large  blood-vessels  has  a  marked  effect  on  body- 
temperature  measurements.  Records  of  the  temperature  in  the 
rectum  give  the  temperature  of  the  body  at  that  point  only.  It  is 
easy  to  believe  that  a  thermometer  inserted  into  a  large  mass  of  fecal 
material  on  one  day  and  into  a  practically  empty  rectum  on  another 
day  would  show  considerable  differences  in  temperature,  particularly 
as  the  response  to  change  in  temperature  would  be  slower  when  the 
mass  of  fecal  matter  was  large.  There  is  therefore  a  daily  variation 
to  be  expected,  no  matter  how  carefully  the  thermometer  is  adjusted 
and  the  readings  made. 

In  noting  the  temperature  changes  during  this  study,  it  appeared 
that  even  when  the  subject  was  standing  quietly,  with  a  preliminary 
interval  long  enough  for  the  thermometer  to  become  settled,  there  was  a 
tendency  for  the  temperature  to  increase  during  the  period.  To 
confirm  this  we  have  taken  the  first  and  last  temperatures  of  all  the 
periods  and  find  that  of  the  approximately  100  periods  hi  which  readings 
were  obtained,  87  per  cent  show  a  higher  temperature  at  the  close  of  the 
standing  period  by  an  average  of  0.07°  C.,  and  9  per  cent  were  lower  at 
the  close  by  an  average  of  0.04°  C.,  while  4  per  cent  show  no  change. 
To  determine  whether  or  not  this  increase  tended  to  accumulate  during 
the  interval  between  the  periods,  also  whether  the  relaxation  from 
motionless  standing  with  removal  of  the  mouthpiece  and  nose-clip  was 
accompanied  by  a  lowering  of  the  temperature,  a  comparison  was  made 
of  the  temperatures  recorded  at  the  end  of  the  standing  periods  with 
those  noted  during  the  intervals  between  the  periods.  In  the  majority 
of  these  cases  there  was  no  marked  change,  and  such  changes  as  were 
noted  were  almost  wholly  in  the  direction  of  a  lowering  of  the  tempera- 
Benedict,  Miles,  and  Johnson,  Proc.  Nat.  Acad.  Sci.,  1919,  5,  p.  218. 


EXPERIMENTS   WITH   SUBJECT   STANDING.  115 

ture.  That  the  temperature  did  not  tend  to  rise,1  as  was  the  case 
during  the  periods  when  the  subject  was  standing  motionless,  would 
indicate  that  the  almost  rigid  position  did  tend  to  increase  the  body- 
temperature  as  recorded.  This  might  be  due  to  the  increased  effort 
made  or  to  limitations  in  the  radiation  from  the  body  resulting  from 
the  use  of  a  blanket,  or  to  an  effort  in  breathing  under  the  conditions 
of  the  period.  The  effort  of  motionless  standing,  therefore,  seemed  to 
cause  a  gradual  rise  in  temperature,  but  this  rise  was  not  permanent 
and  the  average  temperature  of  the  succeeding  periods  remained  very 
much  like  the  average  of  the  first  period. 

The  curves  of  the  body-temperature  records  for  all  of  the  standing 
periods  have  been  plotted;  lack  of  space  prevents  the  printing  of  all  of 
these,  but  a  few  typical  curves  have  been  reproduced  in  connection 
with  subsequent  walking  experiments.  (See  fig.  14,  p.  173,  and  figs.  33 
to  37,  pp.  269  to  275.)  The  observations  within  the  periods  proper  are 
indicated  by  black  points.  The  time  when  the  subject  began  standing 
is  marked  by  the  figure  2.  The  beginning  of  walking  is  indicated  by 
the  figure  3  and  of  sitting  by  the  figure  1.  The  temperatures,  though 
showing  some  fluctuations,  are  fairly  level  for  the  standing  portion  as 
compared  with  the  walking  portions,  while  each  standing  period  shows 
a  tendency  for  the  temperature  to  increase  slightly,  as  previously 
stated. 

BLOOD-PRESSURE  WITH  SUBJECT  STANDING. 

To  secure  data  on  the  effect  upon  the  blood-pressure  of  walking  at 
various  degrees  of  intensity,  it  was  first  necessary  to  obtain  a  base-line 
by  noting  the  blood-pressure  of  the  subject  while  he  was  standing. 
These  data,  which  were  found  for  E.  D.  B.  only,  are  collected  in 
table  6a  for  the  period  from  March  20  to  the  close  of  the  study.  The 
method  by  which  these  measurements  were  made  is  described  on 
page  37. 

The  blood-pressure  during  standing  was  determined  on  20  days  and 
in  three  periods  on  each  day,  except  on  April  10,  when  there  were  but 
two  standing  periods.  The  average  blood-pressure  for  these  20  days 
was  117  mm.,  and  varied  from  109  mm.  on  March  29  to  125  mm.  on 
April  8.  The  difference  between  the  blood-pressures  for  consecutive 
periods  varied  from  0  to  5  mm.,  with  an  average  variation  of  3  mm. 
Of  the  20  days,  there  were  13  on  which  the  pressure  in  the  last  standing 
period  was  higher  than  the  first  by  an  average  of  3.1  mm.  and  six  days 
on  which  the  value  for  the  last  period  was  lower  than  that  for  the  first 
period  by  an  average  of  1.3  mm. ;  on  one  day  there  was  no  change.  It 
would  appear,  therefore,  that  the  effort  of  continued  standing  increased 
the  blood-pressure  slightly.  For  the  wide  range  between  the  extremes 

*It  should  be  noted  that  the  diurnal  temperature  variation  curve  is  characterized  by  a  tendency 
to  rise  rather  than  fall  during  the  forenoon,  i.  e.,  during  the  hours  these  experiments  were  in 
progress. 


116  METABOLISM   DURING   WALKING. 

of  109  for  March  29  and  125  for  April  8,  no  explanation  can  be  found. 
The  readings  of  the  different  determinations  in  each  period  on  both 
dates  are  of  the  same  character  and  it  is  believed  that  the  blood-pres- 
sure on  these  days  was  approximately  as  here  reported.  In  any  event, 
all  readings  are  within  normal  limits  for  a  man  of  this  age  (23  years). 

EXPERIMENTS  WITH  HORIZONTAL  WALKING. 
METABOLISM  OF  SUBJECTS  WHILE  WALKING  ON  A  LEVEL. 

After  the  extensive  researches  of  Durig1  and  his  co-workers  and  the 
report  from  this  Laboratory  on  horizontal  walking  by  Benedict  and 
Murschhauser,2  it  would  seem  but  little,  if  anything,  could  be  added 
to  this  subject  by  multiplying  the  data.  As  a  matter  of  fact,  to  study 
the  influence  of  grade  walking  adequately,  certain  basic  data  for  the 
individual  subjects  employed  in  grade-walking  experiments,  which 
pertain  to  their  metabolism  while  they  were  walking  on  a  level,  are 
essential  for  the  computation  of  the  horizontal  component  in  the  analy- 
sis of  the  grade-walking  experiments.  Accordingly,  horizontal-walk- 
ing experiments  were  made  with  each  of  our  subjects;  in  some  instances 
the  series  extended  over  a  considerable  period  of  time. 

Durig  and  his  associates  found  that  on  the  average  the  energy  re- 
quired with  rates  of  walking  below  80  meters  per  minute  corresponded 
approximately  to  0.55  gram-calorie  for  each  horizontal  kilogrammeter. 
Since  there  were  rather  considerable  differences  in  the  rates  of  walking 
in  this  present  series  of  tests,  the  rate  exceeding  at  tunes  the  normal 
average  walking  speed,  it  is  obvious  that  grand  averages  would  have 
little  value  for  general  comparison,  and  fundamental  data  for  walking 
at  the  several  speeds  is  essential  for  each  series  of  grade-walking  tests. 
Usually,  however,  the  rates  of  walking  ranged  from  50  to  80  meters 
per  minute,  i.  e.,  those  normally  used  by  an  individual  in  "taking  a 
walk,"  and  a  general  picture  of  the  results  is  thus  worthy  of  short  con- 
sideration; consequently,  we  shall  first  discuss  the  values  without  noting 
particularly  the  effect  of  change  in  the  rate  of  walking. 

TOTAL  METABOLISM  DURING  HORIZONTAL  WALKING. 

The  individual  data  for  each  subject  are  given  in  tables  8  to  12. 
The  average  results  are  also  given  for  all  the  subjects  in  table  28, 
these  being  based  primarily  upon  gross  changes  in  the  speed  of  walk- 
ing, expressed  in  5-meter  intervals.  The  following  notes  and  comments 
are  to  be  looked  upon  primarily  as  supplementing  the  original  data 
and  hi  the  nature  of  discussion  of  certain  of  the  results.  Stress  is  laid, 
however,  only  upon  general  figures,  which  take  little,  if  any,  account 
of  differences  in  the  rate  of  walking. 

With  H.  R.  R.,  six  horizontal-walking  experiments  were  made,  with 


rig,  Denkschr.  d.  math.-natur.  Klasse  d.  kaiserl.  Akad.  d.  Wissensch.,  1909,  85,  p.  263. 
*Benedict  and  Murschhauser,  Carnegie  Inst.  Wash.  Pub.  No.  231,  1915. 


EXPERIMENTS   WITH   HORIZONTAL   WALKING.  117 

a  total  of  15  periods.  (See  table  8,  p.  56.)  The  rate  of  walking  varied 
from  59.9  to  67.7  meters  per  minute,  with  an  average  for  the  six  days 
of  62.5  meters  per  minute.  In  the  first  experiment  (March  20)  there 
was  an  unusually  high  metabolism,  the  oxygen  consumption  being 
approximately  100  c.  c.  per  minute  more  than  on  the  next  highest  day, 
and  the  heat-production  about  0.4  calorie  higher.  This  difference  is 
largely  due  to  the  results  of  the  first  period  on  this  date,  which  possibly 
should  have  been  rejected.  The  figures  have,  however,  been  allowed 
to  stand  and  are  used  in  calculating  the  average  value.  The  total 
average  oxygen  consumption  for  H.  R.  R.  was  867  c.  c.  per  minute, 
with  a  heat-output  of  4.17  calories  per  minute. 

With  T.  H.  H.  (table  9,  p.  57)  there  were  seven  days  on  which  experi- 
ments were  made,  with  a  total  of  21  periods.  The  speed  of  walking 
ranged  in  the  individual  periods  only  from  62.4  to  68.2  meters  per 
minute.  February  25,  the  first  day  on  which  T.  H.  H.  acted  as  sub- 
ject, shows  a  much  lower  metabolism  than  that  found  on  the  other 
days,  but  the  fact  that  in  two  of  the  periods  there  was  a  marked  in- 
crease in  the  carbon-dioxide  output  with  a  simultaneous  lowering  of 
the  oxygen  consumption  leads  one  to  question  the  normality  of  the 
conditions  on  this  day.  In  the  experiments  made  from  March  19  to 
April  5,  there  appears  to  have  been  no  marked  change  in  the  metab- 
olism. For  the  seven  days  on  which  horizontal-walking  experiments 
were  made  with  this  subject,  with  a  reasonably  uniform  daily  speed, 
the  average  oxygen  intake  was  678  c.  c.  per  minute  and  the  average 
energy  output  3.30  calories  per  minute. 

The  results  for  W.  K.  were  obtained  in  16  horizontal-walking  experi- 
ments, with  52  experimental  periods.  (See  table  10,  p.  58.)  The 
majority  of  the  experiments  were  made  within  the  month  of  March,  so 
the  picture  is  fairly  continuous.  The  total  heat-output  had  a  tendency 
to  decrease  somewhat  as  time  progressed,  irrespective  of  the  fact  that 
the  average  speeds  differed  in  those  four  weeks  by  a  maximum  of  but 
7  meters  per  minute  from  each  other.  The  last  horizontal-walking 
experiment  was  made  in  June,  three  months  after  most  of  the  experi- 
ments were  carried  out.  This  day  shows  the  lowest  heat-output  of 
any  of  the  horizontal- walking  experiments  with  W.  K.,  but  the  speed  at 
which  the  subject  walked  was  also  the  lowest,  namely,  57.1  meters  per 
minute.  With  this  man  there  was  an  apparent  tendency  for  the  oxy- 
gen consumption  to  be  larger  in  the  first  periods  of  the  day,  with  lower 
values  each  succeeding  period.  The  average  oxygen  consumption  was 
563  c.  c.  per  minute  and  the  average  heat-output  2.72  calories  per 
minute. 

The  largest  number  of  experiments  with  horizontal  walking  was 
made  with  E.  D.  B.,  these  extending  from  October  9, 1915,  to  April  13, 
1916.  (See  table  11,  p.  60.)  During  this  time  measurements  were 
made  on  61  days,  with  198  periods  in  all.  The  range  in  the  daily  aver- 


118  METABOLISM   DURING   WALKING. 

age  speed  was  very  considerable,  i.  e.,  from  35.8  to  97.4  meters  per 
minute.  Since  the  extreme  speeds  at  which  E.  D.  B.  walked  were  not 
natural,  but  forced,  an  average  value  has  therefore  but  little  signifi- 
cance. For  comparison  with  the  results  obtained  with  other  subjects, 
an  average  has  been  found  for  these  days  when  the  speed  of  walking 
fell  within  the  ranges  of  55  to  65  meters  per  minute.  This  shows  a 
total  average  oxygen  consumption  per  minute  of  607  c.  c.  and  a  heat- 
output  of  2.94  calories. 

Considering  the  large  number  of  determined  respiratory  quotients 
of  E.  D.  B.,  it  will  be  found  that  the  quotient  of  the  first  period  of  the 
day  is  usually  higher  than  that  of  subsequent  periods  and  that  the 
difference  between  the  first  and  second  periods  is  usually  greater  than 
that  between  the  second  and  succeeding  periods.  This  is  apparently 
due  to  both  the  carbon  dioxide  and  oxygen,  for,  in  general,  it  may  be 
noted  that  the  elimination  of  the  carbon  dioxide  decreased  and  the 
oxygen  consumption  increased  in  the  second  period.  Since  the  periods 
were  preceded  by  several  minutes  of  preliminary  walking,  any  tendency 
toward  an  unnatural  ventilation  of  the  lungs  would  probably  have 
been  eliminated  before  the  period  began.  Furthermore,  any  change 
in  volume  of  the  ventilating  system  due  to  the  warmth  and  moisture  of 
the  exhaled  air  would  probably  have  been  overcome  by  the  time  the 
final  admission  of  oxygen  was  made.  Such  small  increase  as  there  was 
in  the  temperature  of  the  soda-lime  and  sulphuric  acid  in  the  absorbers 
would  therefore  be  practically  alike  in  all  periods  and  the  effect  would 
be  to  decrease  the  oxygen  admitted  to  the  system  rather  than  to  in- 
crease it.  It  would  seem  from  a  study  of  the  respiratory  quotient  in 
this  connection  that  there  was  a  gradual  change  in  the  character  of  the 
material  oxidized  in  the  body.  If  this  is  not  the  case,  and  if  the  change 
in  the  oxygen  consumption  and  respiratory  quotient  is  in  fact  due  to 
some  fixed  error  in  the  technique,  the  heat-output  as  calculated  for  the 
first  period  is  too  high.  Since  the  heat-output  used,  however,  is 
ordinarily  the  average  of  from  three  to  five  periods,  any  error  due  to 
this  cause  has  no  significance  in  the  general  picture. 

Of  the  three  remaining  subjects  (see  table  12,  p.  68),  the  only  special 
features  to  be  noted  in  the  results  are  that  the  heat-output  for  J.  H.  G. 
was  the  largest  on  his  first  day,  also  that  his  respiratory  quotients  are 
lower  than  those  of  the  subjects  previously  discussed.  The  highest 
heat-output  for  E.  L.  F.  was  on  his  first  day,  although  the  rates  of 
walking  were  fairly  uniform  for  all  three  days.  H.  M.  S.  shows  a  low 
respiratory  quotient,  which  is  La  keeping  with  the  low  respiratory 
quotients  found  in  his  standing  experiments. 

The  average  total  metabolism  for  these  men,  walking  at  what  may 
be  called  natural  speeds,  is  shown  in  table  28.  From  this  table  it  is 
seen  that  the  heat-output  per  kilogram  of  body-weight  per  hour  for  the 
more  natural  speeds  lying  between  50  and  80  meters  per  minute  ranged 


EXPERIMENTS  WITH   HORIZONTAL   WALKING. 


119 


from  2.73  calories  (E.  D.  B.)  to  3.75  calories  (H.  R.  R.).  The  gradual 
increase  in  the  heat-output  on  the  basis  of  body-weight  is  consistent 
throughout  practically  all  the  tests  for  all  of  the  subjects.  There  is 
but  one  exception,  i.  e.,  with  E.  D.  B.  for  60  to  65  meters  per  minute, 
when  the  heat-output  was  higher  than  that  with  the  succeeding  speed 
of  65  to  70  meters  per  minute.  It  may  be  recalled  that  the  series  of 
experiments  with  a  speed  of  60  to  65  meters  per  minute  was  the  first 
series  with  this  subject. 

TABLE  28. — Average  oxygen  consumption  and  heat-output  for  subjects  walking  on  a  level 
at  speeds  between  35  and  100  meters  per  minute. 


Per     kilogram     of 

Subject. 

Speed. 

Oxygen 
per 

Heat 
per 

body-weight 
per  hour. 

w.  "            4. 

•      , 

minute. 

minute. 

Oxygen. 

Heat. 

meters. 

c.  c. 

caZs. 

c.  c. 

caZs. 

A.  J.  O.  .  .   . 

60  to  65 

712 

3.46 

617 

2.99 

H.  R.  R  

60  to  65 

833 

4.00 

713 

3.43 

65  to  70 

902 

4.37 

775 

3.75 

T.  H.  H  

60  to  65 

651 

3.17 

717 

3.49 

65  to  70 

692 

3.36 

763 

3.70 

W.  K.  . 

55  to  60 

519 

2.50 

633 

3.05 

60  to  65 

558 

2.68 

679 

3.27 

65  to  70 

589 

2.86 

717 

3.49 

E.  D.  B  

35  to  40 

467 

2.26 

492 

2.38 

40  to  45 

466 

2.28 

492 

2.40 

45  to  50 

467 

2.29 

492 

2.41 

50  to  55 

535 

2.59 

563 

2.73 

55  to  60 

563 

2.73 

592 

2.88 

60  to  65 

633 

3.06 

667 

3.22 

65  to  70 

586 

2.87 

617 

3.02 

70  to  75 

648 

3.14 

683 

3.30 

75  to  80 

678 

3.31 

713 

3.48 

85  to  90 

864 

4.17 

908 

4.39 

90  to  100 

901. 

4.40 

950 

4.63 

J.  H.  G.  .  . 

50  to  55 

697 

3.32 

617 

2.93 

55  to  60 

710 

3.40 

625 

3.00 

E.  L.  F  

45  to  50 

674 

3.24 

575 

2.76 

50  to  55 

717 

3.46 

604 

2.95 

H.  M.  S.  . 

45  to  50 

601 

2.85 

596 

2.83 

50  to  55 

652 

3.11 

646 

3.09 

The  increase  for  the  heat  per  kilogram  of  body-weight  for  each  in- 
crease of  5  meters  in  speed  is  not  uniform,  either  for  the  different  sub- 
jects or  for  the  different  speeds.  Such  changes  as  2  per  cent  for  J.  H.  G. 
in  passing  from  a  speed  of  50  to  55  meters  per  minute  to  55  to  60  meters 
per  minute,  and  9  per  cent  for  H.  R.  R.  in  passing  from  a  speed  of  60  to 
65  meters  to  65  to  70  meters  per  minute,  are  noted.  In  the  majority 
of  cases  the  variation  ranges  from  5  to  10  per  cent  for  each  increase  of 
5  meters  in  speed.  It  may  be  stated  from  the  data  available  in  the 
table  that  the  heat-output  per  kilogram  of  body-weight  for  all  ordinary 
speeds  of  walking,  such  as  might  be  taken  as  a  "constitutional"  by  a 


120 


METABOLISM   DURING   WALKING. 


person  of  moderate  activity,  would  be  3.35  calories  per  hour  per 
kilogram  of  body-weight. 

INCREMENT  IN  METABOLISM  DUE  TO  HORIZONTAL  WALKING. 

As  has  been  made  evident,  the  values  in  tables  8  to  12  take  no  account 
of  the  basal  standing  requirements  and  only  incidentally  of  the  speeds. 
This  has  been  done  in  tables  29  to  33,  in  which  are  shown  the  body- 
weight  of  the  subject  with  clothing,  the  distance  walked  per  minute, 
the  horizontal  kilogrammeters,  i.  e.,  the  distance  multiplied  by  the 
body-weight,  the  number  of  steps  taken  per  minute,  the  elevation  of 
the  body  in  walking  (step-lift) ,  the  work  done  due  to  such  elevation,  and 
both  the  total  heat-output  and,  of  main  importance  here,  the  incre- 
ments in  the  heat-output  over  the  standing  requirements. 

TABLE  29. — Increase  in  heat-output  of  A.  J.  0.  and  H.  R.  R.  during  horizontal  walking  in  experiments 

without  food.     (Values  per  minute.) 


Date 
and 
condition. 

(a) 

Body- 
weight 
with 
cloth- 
ing. 

(&) 

Dis- 
tance. 

(c) 

Hori- 
zontal 
kilo- 
gram- 
meters. 

0X6 

(d) 

No.  of 

steps. 

(e) 

Rais- 
ing of 
body 
(step- 
lift). 

CO 

Work 
due  to 
step- 
lift. 

a  X   e 

(0) 

Total 
heat. 

Increment  in  heat  above  standing- 
value. 

W 

Total 
in- 
crease. 

(i) 

Per  hori- 
zontal 
kilo- 
gram- 
meter. 

AX  1,000 

CO 
Per  kilo- 
gram- 
meter 
of  step- 
lift. 

h  XI,  000 

(*) 

Propor- 
tion   of 
increase 
due   to 
step-lift. 

2.34X100 

c 

/ 

3 

A.  J.  O. 
1915. 
Feb.  15: 

kg. 

meters. 

meters. 

kg.  m. 

culn. 
1.32" 

cats. 

gm.-cal. 

gm.-cals. 

p.  ct. 

Walking.  .  . 
Feb.  24: 

74.5 

^S.l 

4,701 

3.28 

1.96 

0.417 

1.30 

63.1 
63.8 

4,733 
4,785 

96.9 
96.8 

1.72 
2.01 

129.0 
151.0 

3.67 
3.63 

2.37 
2.33 

.501 

.487 

18.4 
15.4 

13 
15 

Average  . 
Mar.  2: 

75.0 

63.5 

96.9 

1.87 

2.35 

.494 

16.9 

14 

21.31 

Walking 

63.8 
60.7 
63.6 

4,721 
4,492 
4,706 

98.7 
93.8 
97.9 

2.41 
2.01 
1.85 

178.0 
149.0 
137.0 

3.58 
3.37 
3.27 

2.27 
2.06 
1.96 

.481 
.459 
.416 

12.8 
13.8 
14.3 

18 
17 
16 

Average  . 

H.  R.  R. 

1915. 
Mar.  20: 
Standing 

74.0 

62.7 

96.8 

2.09 

2.10 

.452 

13.6 

17 

1.52 

Walking 

67.7 
64.5 

5,030 
4,792 

105.4 
102.2 

.85 
.99 

63.2 
73.6 

4.88 
4.48 

3.36 
2.96 

.668 
.618 

53.2 
40.2 

4 
6 

Average  . 

74.3 

66.1 

103.8 

.92 

3.16 

.643 

46.7 

5 

Average  of  values  for  Feb.  24  and  March  2.     See  table  8,  p.  56. 
'Average  of  values  for  Feb.  15,  24,  and  27.     See  table  3,  p.  43. 


EXPERIMENTS   WITH   HORIZONTAL  WALKING. 


121 


TABLE  29. — Increase  in  heat-output  of  A.  J.  0.  and  H.  R.  R.  during  horizontal  walking  in    experiments 
without  food.     (Values  per  minute.) — Continued. 


Date 
and 
condition. 

(a) 

Body- 
weight 
with 
cloth- 
ing. 

(6) 

Dis- 
tance. 

00 

Hori- 
zontal 
kilo- 
gram- 
meters. 

aX& 

(d) 

No.  of 
steps. 

(e) 

Rais- 
ing of 
body 
(step- 
lift). 

CO 

Work 
due  to 
step- 
lift. 

axe 

(a) 

Total 
heat. 

Increment  in  heat  above  standing- 
value. 

W 

Total 
in- 
crease. 

® 
Per  hori- 
zontal 
kilo- 
gram- 
meter. 

h  X  1,000 

0') 

Per  kilo- 
gram- 
meter 
of  step- 
lift. 

h  x  1,000 

(fc) 
Propor- 
tion of 
increase 
due  to 
step-lift. 

2.34  X  100 

c 

/ 

3 

H.  R.  R.  (Cont.) 
1915 
Mar.  27: 
Standing.  .  . 

kg. 

meters. 

meters. 

kg.  m. 

cols. 
11.34 

cols. 

gm.-cal. 

gm.-cals. 

p.  ct. 

Walking  .  .  . 

65.8 
67.2 
67.5 

4,823 
4,926 
4,948 

102.8 
102.6 
102.4 

1.24 
1.47 
1.34 

90.9 
107.8 
98.2 

4.32 
4.31 
4.36 

2.98 
2.97 
3.02 

0.618 
.603 
.610 

32.8 
27.6 
30.8 

7 
9 
8 

Average  .  . 

Apr.  3: 
Standing 

73.3 

66.8 

102.6 

1.35 

2.99 

.610 

30.4 

8 

ll  34 

Walking  .  .  . 

60.9 
60.5 
60.0 

4,367 
4,338 
4,302 

95.2 
95.0 
95.6 

1.10 
1.11 
1.12 



78.9 
79.6 
80.3 

4.05 
4.10 
4.12 

2.71 
2.76 
2.78 

.621 
.636 
.646 

34.3 
34.7 
34.6 

7 
7 
7 

Average  .  . 

Apr.  10: 
Standing.  .  . 

71.7 

60.5 

95.3 

1.11 

2.75 

.634 

34.5 

7 

1.37 

Walking  .  .  . 

Apr.  17: 

Standing.  .  . 

72.2 

61.1 

4,411 

99.0 

1.02 

73.6 

4.27 

2.90 

.657 

39.4 

6 

1  31 

Walking  .  .  . 

60.0 
59.9 

4,332 
4,325 

98.4 
97.8 

1.00 
1.10 

72.2 
79.4 

3.87 
3.87 

2.56 
2.56 

.591 
.592 

35.5 
32.2 

7 
7 

Average.  . 

Apr.  24: 
Standing.  .  . 

72.2 

60.0 

98.1 

1.05 

2.56 

.592 

33.9 

7 

11.34 

Walking  .  .  . 

61.8 
60.2 
60.6 
60.1 

4,363 
4,250 
4,278 
4,243 

99.2 
95.0 
94.8 
96.0 

1.19 
1.15 
1.25 
1.20 

84.0 
81.2 
88.3 
84.7 

3.87 
3.76 
3.76 
3.82 

2.53 
2.42 
2.41 
2.48 

.580 
.569 
.563 

.584 

30.1 
29.8 
27.3 
29.3 

8 
8 
9 
8 

Average.  . 

70.6 

60.7 

98.3 

1.20 

2.46 

.574 

29.1 

8 

1Average  of  values  for  April  10  and  17.     See  table  3,  p.  43. 


122 


METABOLISM  DURING  WALKING. 


TABLE  30. — Increase  in  heat-output  of  T.  H.  H.  during  horizontal  walking  in  experiments  without  food. 

(Values  per  minute.) 


Date 
and 
condition. 

(a) 

Body- 
weight 
with 
cloth- 
ing. 

(&) 

Dis- 
tance. 

(c) 

Hori- 
zontal 
kilo- 
gram- 
meters. 

0X6 

(<*) 

No.  of 

steps. 

(e) 

Rais- 
ing of 
body 
(step- 
lift). 

(/) 

Work 
due  to 
step- 
lift. 

a  X   e 

(ff) 

Total 
heat. 

Increment  in  heat  above  standing- 
value. 

(A) 

Total 
in- 
crease. 

(i) 
Per  hori- 
zontal 
kilo- 
gram- 
meter. 

h  XI,  000 

(/) 
Per  kilo- 
gram- 
meter 
of  step- 
lift. 

h  XI,  000 

<*) 
Propor- 
tion of 
increase 
due   to 
step-lift. 

2.34X100 

c 

/ 

i 

1915. 
Feb.  25: 

kg. 

meters. 

meters. 

kg.  m. 

cals. 
1.10 

cals. 

gm.-cal. 

gm.-cals. 

p.  ct. 

63.4 
63.7 
63.7 

3,690 
3,707 
3,707 

100.7 
98.3 
97.9 

1.60 
1.18 
2.04 

93.1 
68.7 
118.7 

3.02 

2.98 
2.99 

1.92 
1.88 
1.89 

0.520 
.507 
.510 

20.6 
27.4 
15.9 

11 

9 
15 

Average  . 
Mar.  19: 

58.2 

63.6 

99.0 

1.61 

1.90 

.512 

21.3 

12 

1.14 

Walking.  .  . 

Average  . 

Mar.  22: 
Standing  .  .  . 
Walking.  .  . 

Average  . 

Mar.  24: 
Standing  .  .  . 
Walking.  .. 

Average  . 
Mar.  26: 

65.7 
66.7 
67.1 
67.8 

3,824 
3,882 
3,905 
3,946 

107.0 
106.4 
106.2 
106.0 

1.58 
1.74 
1.85 
1.73 

92.0 
101.3 
107.7 
100.7 

3.44 
3.43 
3.49 
3.41 

2.30 
2.29 
2.35 
2.27 

.601 
.590 
.602 
.575 

25.0 
22.6 
21.8 
22.5 

9 
10 
11 
10 

58.2 

66.8 

106.4 

1.73 

2.30 

.592 

23.0 

10 

1.08 

67.5 
67.5 

3,922 
3,922 

106.6 
105.0 

1.27 
1.30 

73.8 
75.5 

3.47 
3.30 

2.39 
2.22 

.609 
.566 

32.4 
29.4 

7 
8 

58.1 

67.5 

105.8 

1.29 

- 

2.31 

.588 

30.9 

8 

4.  11 

67.4 
68.1 
67.8 

3,788 
3,827 
3,810 

104.8 
104.2 
103.6 

1.86 
1.82 
1.80 

104.5 
102.3 
101.2 

3.34 
3.22 
3.19 

2.23 
2.11 
2.08 

.589 
.551 
.546 

21.3 
20.6 
20.6 

11 
11 
11 

56.2 

67.8 

104.2 

1.83 

2.13 

.562 

20.8 

11 

4.  11 

65.9 
67.6 

68.2 

3,697 
3,792 
3,826 

100.8 
101.2 
102.0 

2.08 
2.16 
2.16 

116.7 
121.2 
121.2 

3.32 
3.18 
3.15 

2.21 
2.07 
2.04 

.598 
.546 
.533 

18.9 
16.1 
16.1 

12 
15 
15 

Average  . 
Mar.  30: 

56.1 

67.2 

101.3 

2.13 

2.11 

.559 

17.0 

14 

4.  11 

"Walking 

65.9 
66.8 
63.5 

3,704 
3,754 
3,569 

102.0 
102.2 
99.8 

2.12 
2.10 
1.87 

119.1 
118.0 
105.1 

3.35 
3.39 
3.27 

2.24 
2.28 
2.16 

.605 
.607 
.605 

18.8 
19.3 
20.6 

12 
12 
11 

Average  . 

56.2 

65.4 

101.3 

2.03 

2.23 

.606 

19.6 

12 

1Average  of  values  for  Feb.  25,  March  19  and  22.     See  table  4,  p.  44. 


EXPERIMENTS   WITH   HORIZONTAL  WALKING. 


123 


TABLE  30. — Increase  in  heat-output  of  T.  H.  H.  during  horizontal  walking  in  experiments  without  food. 

(Values  per  minute.) — Continued. 


(a) 

(b) 

(c) 

(d) 

M 

if) 

(a) 

Increment  in  heat  above  standing- 

value. 

(A) 

(0 

0") 

(jfc) 

Date 
and 
condition. 

Body- 
weight 
with 
cloth- 

Dis- 
tance. 

zontal 
kilo- 
gram- 
meters. 

No.  of 

steps. 

Rais- 
ing of 
body 

(step- 

Work 
due  to 
step- 
lift. 

Total 
heat. 

Total 
in- 
crease. 

Per  hori- 
zontal 
kilo- 
gram- 
meter. 

Per  kilo- 
gram- 
meter 
of  step- 
lift. 

Propor- 
tion of 
increase 
due  to 
step-lift. 

ing. 

0X6 

lift). 

aXe 

h  Xl.OOO 

h  X  1,000 

2.34  XI  00 

c 

/ 

3 

1915. 

Apr.  5: 

kg. 

meters. 

meters. 

kg.  m. 

cals. 

cals. 

gm.-cal. 

gm.-cala. 

p.  ct. 

ll.ll 

Walking    . 

62.4 

3,538 

99.4 

1.69 

95.8 

3.36 

2.25 

0.636 

23.5 

10 

62.7 

3,555 

100.4 

1.80 

102.1 

3.35 

2.24 

.630 

21.9 

11 

63.2 

3,583 

100.8 

1.87 

106.0 

3.42 

2.31 

.645 

21.8 

11 

Average  . 

56.7 

62.8 

100  2 

1.79 

2.27 

.637 

22.4 

11 

Average  of  values  for  Feb.  25,  March  19,  and  22.     See  table  4,  p.  44. 

TABLE  31. — Increase  in  heat-output  of  W.  K.  during    horizontal   walking   in   experiments  without  food. 

(Values  per  minute.) 


Date 
and 
condition. 

(a) 

Body- 
weight 
with 
cloth- 
ing. 

(b) 

Dis- 
tance. 

(c) 

Hori- 
zontal 
kilo- 
gram- 
meters. 

a  X  b 

(<*) 

No.  of 

steps. 

W 

Rais- 
ing of 
body 
(step- 
lift). 

(/) 

Work 
due  to 
step- 
lift. 

o  X  e 

(0) 

Total 
heat. 

Increment  in  heat  above  standing- 
value. 

(h) 

Total 
in- 
crease. 

« 
Per  hori- 
zontal 
kilo- 
gram- 
meter. 

h  XI,  000 

(.0 
Per  kilo- 
gram- 
meter 
of  step- 
lift. 

h  XI,  000 

(fc) 
Propor- 
tion   of 
increase 
due   to 
step-lift. 

2.34X100 

c 

/ 

j 

•     1915. 
Feb.  26: 

Standing 

kg. 

meters. 

meters. 

kg.  m. 

cals. 
1.03 

cals. 

gm.-cal. 

gm.-cals. 

p.  ct. 

Walking.  .  . 

Mar.  4: 
Standing 

52.1 

64.4 

3,355 

114.7 

1.40 

72.9 

2.55 

1.52 

0.453 

20.9 

11 

4.  10 

Walking.  .  . 

64.0 
62.9 
66.0 

3,360 
3,302 
3,465 

115.4 
113.0 
115.2 

1.39 
1.22 
1.21 

73.0 
64.1 
63.5 

3.06 

2.98 
3.08 

1.96 

1.88 
1.98 

.583 
.569 
.571 

26.9 
29.3 
31.2 

9 

8 
8 

Average  . 

Mar.  5: 

Standing  .  .  . 

52.5 

64.3 

114.5 

1.27 

1.94 

.574 

29.1 

8 

4.  10 

Walking.  .  . 

65.3 
65.9 
66.2 

3,435 
3,466 
3,482 

115.3 
114.4 
115.2 

1.56 
1.60 
1.49 

82.0 

84.2 
78.4 

2.93 

2.84 
2.88 

1.83 
1.74 
1.78 

.533 
.502 
.511 

22.3 
20.7 
2S.7 

11 
11 
10 

Average  . 

52.6 

65.8 

115.0 

1.55 

1.78 

.515 

2:.  9 

11 

Average  of  values  obtained  in  experiments  without  food  with  subject  standing,  February  26  to  June  14,  1915, 
nclusive.     (See  table  5,  page  44.) 


124 


METABOLISM   DURING   WALKING. 


TABLE  31. — Increase  in  heat-output  of  W.  K.  during  horizontal  walking  in  experiments  without  food. 

(Values  per  minute.) — Continued. 


Date 
and 
condition. 

(a) 

Body- 
weight 
with 
cloth- 
ing. 

(&) 

Dis- 
tance. 

(c) 

Hori- 
zontal 
kilo- 
gram- 
meters. 

a  Xb 

(d) 

No.  of 

steps. 

<«) 

Rais- 
ing of 
body 
(step- 
lift). 

CO 

Work 
due  to 
step- 
lift. 

axe 

(0) 

Total 
heat. 

Increment  in  heat  above  standing- 
value. 

W 

Total 
in- 
crease. 

CO 

Per  hori- 
zontal 
kilo- 
gram- 
meter. 

h  X  1,000 

(/) 
Per  kilo- 
gram- 
meter 
of  step- 
lift. 

hx  1,000 

(W 

Propor- 
tion of 
increase 
due  to 
step-lift. 

2.34  XlOO 

c 

/ 

1 

1915. 
Mar.  8: 
Standing 

kg. 

meters. 

meters. 

kg.  m. 

cals. 
11.10 

cals. 

gm.-cal. 

gm.-cals. 

p.  ct. 

66.4 
66.6 
66.6 

3,486 
3,497 
3,497 

116.6 
116.0 
115.6 

1.48 
1.52 
1.46 

77.7 
79.8 
76.7 

2.99 
2.87 
2.83 

1.89 
1.77 
1.73 

0.542 
.506 
.495 

24.3 
22.2 
22.6 

10 
11 
10 

Average  . 

Mar.  9: 
Standing 

52.5 

66.5 

116.1 

1.49 



1.80 

.514 

23.0 

10 

U.IO 

Walking  .  .  . 

66.0 
62.5 
62.2 
58.6 

3,439 
3,256 
3,241 
3,053 

115.6 
108.6 
109.0 
107.6 

1.13 
.91 
1.00 
.83 

58.9 
47.4 
52.1 
43.2 

3.01 
2.65 
2.57 
2.47 

1.91 
1.55 
1.47 
1.37 

.555 
.476 
.454 
.449 

32.4 
32.7 
27.3 
31.7 

7 
7 
9 
7 

Average  . 

Mar.  12  : 
Standing 

52.1 

62.3 



110.2 

.97 

1.58 

.484 

31.0 

8 

1.05 

Walking.  . 

60.9 
58.5 
68.2 

3,179 
3,054 
3,560 

111.2 
109.8 
117.6 

1.17 
1.13 
1.33 

61.1 
59.0 
69.4 

2.82 
2.48 
2.76 

1.77 
1.43 
1.71 

.557 
.468 
.480 

29.0 
24.2 
24.6 

8 
10 
9 

Average  . 

Mar.  13: 
Standing... 

52.2 

62.5 

112.9 

1.21 

1.64 

.502 

25.9 

9 

1.21 

Walkinj.  . 

65.1 
64.7 
59.4 
59.1 

3,333 
3,313 
3,041 
3,026 

114.0 
113.0 
108.0 
107.4 

1.01 
1.04 
.95 
1.26 

51.7 
53.2 
48.6 
64.5 

2.87 
2.78 
2.85 
2.63 

1.66 
1.57 
1.64 
1.42 

.498 
.474 
.539 
.469 

32.1 
29.5 
33.7 
22.0 

8 
8 
7 
11 

Average  . 

Mar.  16: 
Standing.  .  . 

51.2 

62.1 

110.6 

1.07 

1.57 

.495 

29.3 

8 

1.03 

Walking.  .  . 

59.2 
62.3 
60.9 
60.6 

3,108 
3,271 
3,197 
3,182 

109.8 
112.4 
107.2 
103.6 

.70 

.87 
.85 
.81 

36.8 
45.7 
44.6 
42.5 

2.70 
2.64 
2.86 
2.69 

1.67 
1.61 
1.83 
1.66 

.537 
.492 
.572 
.522 

45.4 
35.2 
41.0 
39.1 

5 

7 
6 
6 

Average  . 

52.5 

60.8 

108.3 

.81 

1.69 

.531 

40.2 

6 

1Average  of  talues  obtained  in  experiments  without  food  with  subject  standing,  February  26  to  June  14,  1915, 
inclusive.     (Se«  table  5,  page  44.) 


EXPERIMENTS   WITH   HORIZONTAL  WALKING. 


125 


TABLE  31. — Increase  in  heat-output  of  W.  K.  during  horizontal  walking  in  experiments  without  food. 

(Values  per  minute.') — Continued. 


Date 
and 
condition. 

(a) 

Body- 
weight 
with 
cloth- 
ing. 

(6) 

Dis- 
tance. 

(e) 

Hori- 
zontal 
kilo- 
gram- 
meters. 

0x6 

(d) 

No.  of 
steps. 

(e) 

Rais- 
ing of 
body 
(step- 
lift). 

(/) 

Work 
due  to 
step- 
lift. 

o  Xe 

(0) 

Total 
heat. 

Increment  in  heat  above  standing- 
value. 

W 

Total 
in- 
crease. 

(0 
Per  hori- 
zontal 
kilo- 
gram- 
meter. 

h  X  1,000 

(3) 
Per  kilo- 
gram- 
meter 
of  step- 
lift. 

fcXl.OOO 

(*) 
Propor- 
tion of 
increase 
due  to 
step-lift. 

2.34  XlOO 

c 

/ 

j 

1915. 
Mar.  17: 
Standing  .  .  . 

kg. 

meters. 

meters. 

kg.  m. 

cols. 
1.21 

cals. 

gm.-cal. 

gm.-cals. 

p.ct. 

Walking.  .  . 

67.3 
67.4 
67.8 
67.5 

3,520 
3,525 
3,546 
3,530 

117.2 
116.8 
116.2 
114.6 

1.41 
1.48 
1.42 
1.51 

73.7 
77.4 
74.3 
79.0 

2.99 
2.77 

2.78 
2.76 

1.78 
1.56 
1.57 
1.55 

0.506 
.443 
.443 
.439 

24.2 
20.2 
21.1 
19.6 

10 
12 

11 
12 

Average  . 

Mar.  18: 
Standing.  .  . 

52.3 

67.5 

116.2 

1.46 

1.62 

.458 

21.3 

11 

1.03 

Walking  .  .  . 

62.5 
58.4 
60.8 
58.8 

3,288 
3,072 
3,198 
3,093 

108.0 
100.0 
106.2 
104.2 

1.05 
.84 
1.12 
1.01 

55.2 
44.2 
58.9 
53.1 

2.78 
2.60 
2.58 
2.54 

1.75 
1.57 
1.55 
1.51 

.532 
.511 
.485 

.488 

31.7 
35.5 
26.3 

28.4 

7 
7 
9 
8 

Arerage  . 

Mar.  23: 
Standing.  .  . 

52.6 

60.1 

104.6 

1.01 

1.60 

.504 

30.5 

8 

n.io 

Walking  .  .  . 

64.3 
66.4 
66.5 

3,247 
3,353 
3,358 

111.6 
113.4 
111.4 

1.12 
1.34 
1.39 

56.6 
67.7 
70.2 

2.82 
2.77 
2.70 

1.72 
1.67 
1.60 

.530 
.498 
.476 

30.4 
24.7 
22.8 

8 
10 
10 

Average  . 

Mar.  25: 
Standing 

50.5 

65.7 

112.1 

1.28 

1.66 

.501 

26.0 

9 

Jl  10 

Walking.  . 

67.3 
67.5 
67.0 

3,399 
3,409 
3,384 

114.6 
113.4 
110.2 

2.02 
2.07 
1.99 

102.0 
104.5 
100.5 

3.00 
2.99 
2.72 

1.90 
1.69 
1.62 

.559 
.496 
.479 

18.6 
16.2 
16.1 

13 
14 
15 

Average  . 

Mar.  29: 

Standing  .  .  . 

50.5 

67.3 

112.7 

2.03 

1.74 

.511 

17.0 

14 

4.  10 

Walking  .  .  . 

63.3 
60.8 
62.8 

3,178 
3,052 
3,153 

109.0 
108.2 
110.6 

1.31 
1.06 
1.15 

65.8 
53.2 
57.7 

2.58 
2.55 
2.54 

1.48 
1.45 
1.44 

.466 
.475 
.457 

22.5 
27.3 
25.0 

10 
9 
9 

Average  . 

50.2 

62.3 

109.3 

1.17 

1.46 

.466 

24.9 

10 

1  Average  of  values  obtained  in  experiments  without  food  with  subject  standing,  February  26  to  June  14,  1915, 
inclusive.     (See  table  5,  page  44.) 


126 


METABOLISM   DURING   WALKING. 


TABLE  31. — Increase  in  heat-output  of  W.  K.  during  horizontal  walking  in  experiments  without  food, 

(Values  per  minute.) — Continued. 


Date 
and 
condition. 

(a) 

Body- 
weight 
with 
cloth- 
ing. 

(b) 

Dis- 
tance. 

(e) 

Hori- 
zontal 
kilo- 
gram- 
meters. 

o  X& 

(A 

No.  of 

steps. 

(«) 

Rais- 
ing of 
body 
(step- 
lift). 

CO 

Work 
due  to 
step- 
lift. 

axe 

(a) 

Total 
heat. 

Increment  in  heat  above  standing- 
value. 

(*) 

Total 
in- 
crease. 

« 
Per  hori- 
zontal 
kilo- 
gram- 
meter. 

h  X  1,000 

0") 
Per  kilo- 
gram- 
meter 
of  step- 
lift. 

h  X  1,000 

(*) 
Propor- 
tion of 
increase 
due  to 
step-lift. 

2.34  xlOOJ 

c 

/ 

' 

1915 
Mar.  31: 
Standing.  .  . 

kg. 

meters. 

meters. 

kg.  m. 

cats. 
'1.10 

cols. 

gm.-cal. 

gm.-cals. 

p.  ct. 

Walking  .  .  . 

64.8 
65.8 
64.8 
64.9 

3,305 
3,356 
3,305 
3,310 

108.2 
109.8 
109.6 
107.6 

1.17 
1.20 
1.18 
1.17 

59.7 
61.2 
60.2 
59.7 

2.58 
2.61 
2.55 
2.50 

1.48 
1.51 
1.45 
1.40 

0.448 
.450 
.439 
.423 

24.8 
24.7 
24.1 
23.5 

9 
10 
10 

10 

Average  . 

June  23: 
Standing  .  .  . 

51.0 

65.1 

108.8 

1.18 

1.46 

.440 

24.3 

10 

*1  10 

Walking  .  .  . 

58.2 
57.1 
56.0 

2,904 
2,849 
2,794 

108.0 
106.0 
105.4 

1.30 
1.36 
1.19 

64.9 
67.9 
59.4 

2.31 
2.28 
2.21 

1.21 
1.18 
1.11 

.417 
.414 
.397 

18.6 
17.4 
18.7 

13 
13 
13 

Average  . 

49.9 

57.1 

106.5 

1.28 

1.17 

.409 

18.2 

13 

1  Average  of  values  obtained  in  experiments  without  food  with  subject  standing,  February  26  to  June  14, 1915, 
inclusive.     (See  table  5,  page  44.) 

TABLE  32. — Increase  in  heat-output  of  E.  D.  B.  during  horizontal'  walking  in   experiments  without  food, 

(Values  per  minute.) 


(a) 

(b) 

(c) 

(d) 

(e) 

CO 

(0) 

Increment  in  heat  above  standing- 

value. 

Body- 

Hori- 
zontal 

Rais- 

Work 

(h) 

<t) 

(j) 

(fc) 

Date 
and 
condition. 

weight 
with 
cloth- 

Dis- 
tance. 

kilo- 
gram- 
meters. 

No.  of 

steps. 

ing  of 
body 
(step- 

due  to 
step- 
lift. 

Total 
heat. 

Total 

Per  hori- 
zontal 
kilo- 

Per kilo- 
gram- 
meter 

Propor- 
tion   of 
increase 

ing. 

lift). 

in- 

gram- 

of  step- 

due   to 

a   X  b 

a    X  e 

crease. 

meter. 

lift. 

step-lift. 

h  XI.  000 

hX  1,000 

2.34X100 

c 

/ 

i 

1915. 

Oct.  9: 

kg. 

meters. 

meters. 

kg.  m. 

cals. 

cals. 

gm.-cal. 

gm.-cals. 

p.  ct. 

Standing.  .  . 

1  19 

Walking.  .  . 

57.8 

3,468 

94  2 

3  36 

2  17 

0  626 

56  4 

3,384 

91  8 

1  30 

78  00 

3  15 

1  96 

579 

25  1 

9 

Average  . 

60.0 

57.1 

93.0 

1.30 

2.07 

.603 

25.1 

9 

EXPERIMENTS   WITH   HORIZONTAL   WALKING. 


127 


TABLE  32. — Increase  in  heat-output  of  E.  D.  B.  during  horizontal  walking  in  experiments  without  food. 

(Values  per  minute.) — Continued. 


Date 
and 
condition. 

(a) 

Body- 
weight 
with 
cloth- 
ing. 

<&) 

Dis- 
tance. 

(«) 

Hori- 
zontal 
kilo- 
gram- 
meters. 

a  X6 

w 

No.  of 

steps. 

<«) 

Rais- 
ing of 
body 
(step- 
lift). 

CO 

Work 
due  to 
step- 
lift. 

aXe 

(0) 

Total 
heat. 

Increment  in  heat  above  standing- 
value. 

(h) 

Total 
in- 
crease. 

« 
Per  hori- 
zontal 
kilo- 
gram- 
meter. 

h  X  1,000 

0") 
Per  kilo- 
gram- 
meter 
of  step- 
lift. 

h  X  1,000 

W 
Propor- 
tion of 
increase 
due  to 
step-lift. 

2.34  XlOO 

c 

/ 

i 

1915. 
Oct.  11: 

Standing  .  .  . 

kg. 

meters. 

meters. 

kg.  m. 

cals. 
1.13 

cals. 

gm.-cal. 

gm.-cah. 

p.  ct. 

Walking  .  . 

56.3 
53.7 

3,401 
3,243 

89.0 
96.8 

1.45 
1.34 

87.58 
80.94 

2.99 
2.98 

1.86 
1.85 

0.547 
.570 

21.2 
22.9 

11 
10 

Average  . 

Oct.  13: 

Standing  .  .  . 

60.4 

55.0 

92.9 

1.40 

1.86 

.559 

22.1 

11 

1.12 

Walking  .  .  . 

Oct.  14: 

Standing 

60.2 

55.8 

3,359 

87.0 

1.34 

80.67 

2.93 

1.81 

.539 

22.4 

10 

1.13 

Walking  .  .  . 

55.3 
54.2 
54.1 

3,318 
3,252 
3,246 

88.4 
88.2 
87.8 

1.34 
1.34 
1.34 

80.40 
80.40 
80.40 

2.80 
2.85 
2.91 

1.67 
1.72 
1.78 

.503 
.529 

.548 

20.8 
21.4 
22.1 

11 
11 

11 

Average  . 

Oct.  15: 
Standing  . 

60.0 

54.5 

88.1 

1.34 

1.72 

.527 

21.4 

11 

1.10 

Walking  . 

55.4 
54.3 
53.6 

3,252 
3,187 
3,146 

88.9 
88.1 
89.4 

1.24 

72.79 

2.77 
2.83 
2.90 

1.67 
1.73 
1.80 

.514 
.543 
.572 

22.9 

10 

Average  . 

Oct.  16: 

Standing  .  . 

1.06 

62.22 

28.9 

8 

58.7 

54.4 

88.8 

1.15 

1.73 

.543 

25.9 

9 

1  06 

Walking.  . 

65.2 
64.9 
65.0 
64.9 

3,834 
3,816 
3,822 
3,816 

98.0 
97.4 
97.6 
97.4 

1.65 
1.74 
1.69 
1.85 

97.02 
102.31 
99.37 
108.78 

2.95 
3.01 
3.05 
3.02 

1.89 
1.95 
1.99 
1.96 

.493 
.511 
.521 
.514 

19.5 
19.1 
20.0 
18.0 

13 
12 
12 
13 

Average  . 

Oct.  18: 

Standing.  .  . 

58.8 

65.0 

97.6 

1.73 

1.95 

.510 

19.2 

12 

1.12 

Walking  .  .  . 

63.4 
64.5 
64.4 
64.8 

3,760 
3,825 
3,819 
3,843 

96.6 
97.2 
94.4 
97.4 

1.49 
1.85 
1.83 
1.93 

88.36 
109.71 
108.52 
114.45 

2.87 
3.01 
2.95 
3.01 

1.75 
1.89 
1.83 
1.89 

.465 
.494 
.479 
.492 

19.8 
17.2 
16.9 
16.5 

12 
14 
14 
14 

Average  . 

59.3 

64.3 

96.4 

1.78 

1.84 

.483 

17.6 

14 

128 


METABOLISM   DURING   WALKING. 


TABLE  32. — Increase  in  heat-output  of  E.  D.  B.  during  horizontal  walking  in  experiments  without  food. 

(Values  per  minute.) — Continued. 


Date 
and 
condition. 

(a) 

Body- 
weight 
with 
cloth- 
ing. 

<W 

Dis- 
tance. 

(c) 

Hori- 
zontal 
kilo- 
gram- 
metera. 

a  X& 

(<*) 

No.  of 

steps. 

(•) 

Rais- 
ing of 
body 
(step- 
lift). 

CO 

Work 
due  to 
step- 
lift. 

axe 

(a) 

Total 
heat. 

Increment  in  heat  above  standing- 
value. 

(h) 

Total 
in- 
crease. 

(0 
Per  hori- 
zontal 
kilo- 
gram- 
meter. 

h  xl.OOO 

(/) 
Per  kilo- 
gram- 
meter 
of  step- 
lift. 

fcXl.OOO 

(V 
Propor- 
tion of 
increase 
due  to 
step-lift. 

2.34  XlOO 

c 

/ 

3 

1915. 
Oct.  19: 

Standing  .  .  . 
Walking  .  .  . 

kg. 

meters. 

meters. 

kg.  m. 

cals. 
1.14 

cals. 

gm.-cal. 

gm.-cah. 

p.ct. 

64.6 
64.1 
63.9 
64.5 

3,818 
3,788 
3,776 
3,812 

97.0 
96.4 
96.4 
96.2 

1.69 
1.89 
1.89 
1.85 

99.88 
111.70 
111.70 
109.34 

2.90 
3.14 
2.97 
3.19 

1.76 
2.00 
1.83 
2.05 

0.461 
.528 
.485 
.538 

17.6 
17.9 
16.4 
18.8 

13 
13 
14 

12 

Average  . 

Oct.  20: 
Standing  .  .  . 

59.1 

64.3 

96.5 

1.83 

1.91 

.503 

17.7 

13 

1.13 

Walking  .  .  . 

64.6 
64.4 
64.7 
64.5 
64.7 

3,798 
3,787 
3,804 
3,793 
3,804 

97.4 
97.0 
97.8 
97.8 
98.2 

1.85 
1.89 
1.85 
1.85 
1.93 

108.78 
111.13 
108.78 
108.78 
113.48 

3.00 
3.13 
3.12 
3.10 
3.11 

1.87 
2.00 
1.99 
1.97 
1.98 

.492 
.528 
.523 
.519 
.521 

17.2 
18.0 
18.3 
18.2 
17.5 

14 
13 
13 
13 
13 

Average  . 

Oct.  21: 

Standing  .  .  . 

58.8 

64.6 

97.6 

1.87 

1.96 

.517 

17.8 

13 

1.08 

Walking.  .  . 

63.8 
63.6 
63.7 
63.8 
64.3 

3,828 
3,816 
3,822 
3,828 
3,858 

98.4 
97.6 
97.0 
96.8 
96.7 

2.97- 
3.07 
3.08 
3.11 
3.07 

1.89 
1.99 
2.00 
2.03 
1.99 

.494 
.521 
.523 
.530 
.516 

Average  . 

Oct22: 

Standing  .  .  . 

1.85 
1.89 
1.89 
1.86 

111.00 
113.40 
113.40 
111.60 

17.9 
17.5 
17.9 
17.8 

13 
13 
13 
13 

60.0 

63.8 

97  3 

1  87 

1.98 

.517 

17.8 

13 

1  06 

Walking  .  .  . 

71.6 
72.6 
72.6 
72.4 

4,246 
4,305 
4,305 
4,293 

101.0 
100.6 
99.6 
100.7 

2.20 
1.97 
2.01 

130.46 
116.82 
119.19 

3.12 
3.17 
3.20 
3.22 

2.06 
2.11 
2.14 
2.16 

.485 
.490 
.497 
.503 

15.8 
18.1 
18.0 

15 
13 
13 

Average  . 

Oct.  23: 

Standing  .  .  . 

59.3 

72.3 

100.5 

2.06 

2.12 

.494 

17.3 

14 

1  07 

Walking.  .. 

71.6 
72.4 
72.2 
72.6 

4,260 
4,308 
4,296 
4,320 

101.8 
101.0 
100.6 
100.8 

1.99 
2.01 
2.20 
2.30 

118.41 
119.60 
130.90 
136.85 

3.23 
3.25 
3.19 
3.25 

2.16 
2.18 
2.12 
2.18 

.507 
.506 
.493 
.505 

18.3 
18.1 
16.2 
15.9 

13 
13 
14 

15 

Average  . 

59.5 

72.2 

101.1 

2.13 

2.16 

.503 

17.1 

14 

EXPERIMENTS   WITH   HORIZONTAL   WALKING. 


129 


TABLE  32. — Increase  in  heat-output  of  E.  D.  B.  during  horizontal  walking  in  experiments  without  food. 

(Values  per  minute.) — Continued. 


Date 
and 
condition. 

(a) 

Body- 
weight 
with 
cloth- 
ing. 

<W 

Dis- 
tance. 

M 

Hori- 
zontal 
kilo- 
gram- 
meters. 

a  X  b 

<d) 

No.  of 

steps. 

(e) 

Rais- 
ing of 
body 
(step- 
lift). 

(/) 

Work 
due  to 
step- 
lift. 

a  X  e 

(a) 

Total 
heat. 

Increment  in  heat  above  standing- 
value. 

(*) 

Total 
in- 
crease. 

(0 

Per  hori~ 
zontal 
kilo- 
gram- 
meter. 

hX  1,000 

Cfl 

Per  kilo- 
gram- 
meter 
of  step- 
lift. 

AX  1,000 

(*) 
Propor- 
tion of 
increase 
due   to 
step-lift. 

2.34X100 

c 

/ 

; 

1915. 
Oct.  25: 
Standing.  .  . 

If. 

meters. 

meters. 

kg.  m. 

cats. 
1.07 

cols. 

gm.-cal. 

gm.-cals. 

p.ct. 

Walking  .  .  . 

72.5 
72.9 
73.0 
73.7 
73.7 

4,278 
4,301 
4,307 
4,348 
4,348 

101.4 
101.1 
101.4 
101.4 
101.4 

2.28 
2.60 
2.48 
2.59 
2.53 

134.52 
153.40 
146.32 
152.81 
149.27 

3.12 
3.22 
3.22 
3.24 
3.27 

2.05 
2.15 
2.15 
2.17 
2.20 

0.479 
.500 
.499 
.499 
.506 

15.9 
14.0 
14.7 
14.1 
14.7 

15 
17 
16 
17 
16 

Average  . 

Oct.  26: 

Standing  .  .  . 

59.0 

73.2 

101.4 

2.50 

2.14 

.497 

14.7 

16 

1.06 

Walking  .  .  . 

72.5 
72.2 
73.5 
72.9 
73.2 

4,234 
4,216 
4,292 
4,257 
4,275 

103.0 
101.8 
102.4 
102.6 
102.2 

2.38 
2.50 
2.52 
2.46 
2.50 

139.00 
146.00 
147.17 
143.66 
146.00 

3.15 
3.19 
3.25 
3.19 
3.23 

2.09 
2.13 
2.19 
2.13 
2.17 

.494 
.505 
.510 
.500 
.508 

15.0 
14.6 
14.9 
14.8 
14.9 

16 
16 
16 
16 
16 

Average  . 

Oct.  27: 

Standing.  .  . 

58.4 

72.9 

102  4 

2  47 

2.14 

.503 

14.8 

16 

1.07 

Walking  .  .  . 

76.6 
77.0 
77.3 
78.3 
78.5 
78.6 

4,481 
4,505 
4,522 
4,581 
4,592 
4,598 

104.2 
103.8 
104.4 
104.6 
105.0 
105.0 

2.75 
2.94 
2.92 
2.98 
2.94 
2.95 

160.88 
171.99 
170.82 
174.33 
171.99 
172.58 

3.22 
3.27 
3.30 
3.38 
3.40 
3.44 

2.15 
2.20 
2.23 
2.31 
2.33 
2.37 

.480 
.488 
.493 
.504 
.507 
.515 

13.4 
12.8 
13.1 
13.3 
13.5 
13.7 

18 
18 
18 
18 
17 
17 

Average  . 

Oct.  28: 

Standing  . 

58.5 

77.7 

104.5 

2.91 

2.27 

.498 

13.3 

18 

1.08 

Walking  .  .  . 

77.1 
77.8 
77.8 
78.1 
78.2 

4,526 
4,567 
4,567 
4,584 
4,590 

106.6 
106.6 
105.8 
106.4 
107.2 

2.57 
2.67 
2.83 
2.95 
2.90 

150.86 
156.73 
166.12 
173.17 
170.23 

3.23 
3.29 
3.33 
3.36 
3.30 

2.15 
2.21 
2.25 
2.28 
2.22 

.475 

.484 
.493 
.497 

.484 

14.2 
14.1 
13.5 
13.2 
13.0 

17 
16 
17 

18 
18 

Average  . 

Oct.  29: 

Standing  . 

58.7 

77.8 

106.5 

2.78 

2.22 

.487 

13.6 

17 

1.09 

Walking  .  .  . 

77.1 
78.1 
78.3 

78.5 

4,557 
4,616 
4,628 
4,639 

104.4 
106.1 
104.4 
104.4 

2.97 
2.90 
2.95 
2.99 

175.53 
171.39 
174.35 
176.71 

3.36 
3.33 
3.40 
3.50 

2.27 
2.24 
2.31 
2.41 

.498 
.485 
.499 
.520 

12.9 
13.1 
13.2 
13.6 

18 
18 
18 
17 

Average  . 

59.1 

78.0 

104.8 

2.95 

2.31 

.501 

13.2 

18 

130 


METABOLISM   DURING   WALKING. 


TABLE  32. — Increase  in  heat-output  of  E.  D.  B.  during  horizontal  walking  in  experiments  without  food. 

(Values  per  minute.') — Continued. 


Date 
and 
condition. 

(o) 

Body- 
weight 
with 
cloth- 
ing. 

(6) 

Dis- 
tance. 

(c) 

Hori- 
zontal 
kilc- 
gram- 
meters. 

o  X  b 

(d) 

No.  of 

steps. 

(«) 

Rais- 
ing of 
body 
(step- 
lift). 

(/) 

Work 
due  to 
step- 
lift. 

o  X  e 

(<7) 

Total 
heat. 

Increment  in  heat  above  standing- 
value. 

W 

Total 
in- 
crease. 

(0 
Per  hori- 
zontal 
kilo- 
gram- 
meter. 

hX  1,000 

Cfl 

Per  kilo- 
gram- 
meter 
of  step- 
lift. 

^X  1,000 

<*) 
Propor- 
tion   of 
increase 
due   to 
step-lift. 

2.34X100 

c 

/ 

3 

1915. 
Oct.  30: 

Standing 

kg. 

meters. 

meters. 

kg.  m. 

cals. 
4.08 

cals. 

gm.-cal. 

gm.-cals. 

p.  ct. 

Walking  .  .  . 

45.2 
43.5 
43.1 

2,653 
2,553 
2,530 

80.0 
81.0 

79.8 

0.70 
.68 
.61 

41.09 
39.92 
35.81 

2.42 
2.32 
2.34 

1.34 
1.24 
1.26 

0.505 
.486 
.498 

32.6 
31.1 
32.4 

7 
8 
7 

Average  . 

Nov.  1  : 
Standing  . 

58.7 

43.9 

80.3 

.66 

1.28 

.496 

32.0 

7 

4.08 

Walking  .  .  . 

44.9 
44.5 
43.5 

2,649 
2,626 
2,567 

79.2 
80.0 
79.8 

.75 
.70 
.72 

44.25 
41.30 

42.48 

2.33 
2.31 
2.32 

1.25 
1.23 
1.24 

.472 
.468 
.483 

28.2 
29.8 
29.2 

8 
8 
8 

Average  . 

'  Nov.  2: 
Standing  .  .  . 

59.0 

44.3 

79.7 

.72 

1.24 

.474 

29.1 

8 

4.08 

Walking  .  .  . 

43.9 
43.4 
42.3 

2,577 
2,648 
2,483 

80.8 
79.4 
79.4 

.73 

.72 
.64 

42.85 
42.26 
37.57 

2.31 
2.35 
2.30 

1.23 
1.27 
1.22 

.477 
.498 
.491 

28.7 
30.0 
32.4 

8 
8 
7 

Average  . 

Nov.  3: 

Standing  .  .  . 

58.7 

43.2 

79.9 

.70 

. 

1.24 

.489 

30.4 

8 

4.08 

Walking  .  . 

45.4 
44.7 
43.4 

2,674 
2,633 
2,556 

80.8 
80.0 
95.2 

.75 
.84 
.69 

44.18 
49.48 
40.64 

2.27 
2.28 
2.23 

1.19 
1.20 
1.15 

.445 
.456 
.450 

26.9 
24.2 
28.3 

9 
10 

8 

Average  . 

Nov.  4  : 
Standing.  .  . 

58.9 

44.5 

85.3 

.76 

1.18 

.450 

26.5 

9 

4.08 

Walking.  . 

53.5 
53.2 
53.9 

3,119 
3,102 
3,142 

86.4 
86.4 
86.6 

1.17 
1.11 
1.24 

68.21 
64.71 
72.29 

2.43 
2.45 
2.54 

1.35 
1.37 
1.46 

.433 

.442 
.465 

19.8 
21.2 
20.2 

12 
11 
12 

Average  . 

Nov.  5: 
Standing  .  .  . 

58.3 

53.5 

86.5 

1.17 

1.39 

.447 

20.4 

12 

4  08 

Walking  .  . 

46.9 
46.2 
45.6 

2,739 
2,698 
2,663 

82.2 
81.8 
81.6 

.85 
.80 
.79 

49.64 
46.72 
46.14 

2.32 
2.32 
2.32 

1.24 
1.24 
1.24 

.453 
.460 
.466 

25.1 
26.6 
26.9 

9 
9 
9 

Average  . 

58.4 

46.2 

81.9 

.81 

1.24 

.460 

26.2 

9 

Average  of  values  obtained  in  experiments  without  food,  with  subject  standing,  October  11  to  December  22, 
1915,  inclusive.     (See  table  6,  page  46.) 


EXPERIMENTS   WITH   HORIZONTAL  WALKING. 


131 


TABLE  32. — Increase  in  heat-output  of  E.  D.  B.  during  horizontal  walking  in  experiments  without  food. 

(Values  per  minute.) — Continued. 


Date 
and 
condition. 

(a) 

Body- 
weigh' 
with 
cloth- 
ing. 

<« 

Dis- 
tance. 

(c) 

Hori- 
zontal 
kilo- 
gram- 
meters 

a  X  b 

(d) 

No.  of 
steps. 

w 

Rais- 
ing of 
body 
(step- 
lift). 

</) 

Work 
due  to 
step- 
lift. 

o  X  « 

(a) 

Total 
heat. 

Increment  in  heat  above  standing- 
value. 

(h) 

Total 
in- 
crease. 

« 
Per  hori- 
zontal 
kilo- 
gram- 
meter. 

AX  1,000 

CO 
Per  kilo- 
gram- 
meter 
of  step- 
lift. 

AX1.000 

(*) 
Propor- 
tion   of 
increase 
due  to 
step-lift. 

2.34X100 

c 

/ 

3 

1915. 
Nov.  6: 
Standing  .  .  . 

kg. 

meters. 

meters. 

kg.  m. 

cats. 
4.08 

cats. 

gm.-cal. 

gm.-cals. 

p.ct. 

Walking.  .  . 

46.8 
45.8 
45.0 

2,747 
2,688 
2,642 

82.0 
80.8 
79.6 

0.76 
.76 
.73 

44.61 
44.61 
42.85 

2.24 
2.25 
2.26 

1.16 
1.17 
1.18 

0.422 
.435 

.447 

26.0 
26.3 
27.5 

9 
9 
9 

Average  . 

Nov.  8: 
Standing  .  .  . 

58.7 

45.9 

80.8 

.75 

1.17 

.435 

26.6 

9 

4.08 

Walking  .  .  . 

55.2 
56.1 
57.0 

3,257 
3,310 
3,363 

89.0 

88.2 
89.8 

1.19 
1.32 
1.28 

70.21 
77.88 
75.52 

2.54 
2.59 
2.59 

1.46 
1.51 
1.51 

.448 
.456 
.449 

20.8 
19.4 
20.0 

11 
12 
12 

Average  . 

Nov.  9: 
Standing  .  .  . 

59.0 

56.1 

89.0 

1.26 

1.49 

.451 

20.1 

12 

4.08 

Walking  .  .  . 

54.9 
54.5 
54.6 

3,228 
3,205 
3,210 

88.8 
87.6 
87.6 

1.17 
1.16 
1.23 

68.80 
68.21 
72.32 

2.42 
2.41 
2.46 

1.34 
1.33 
1.38 

.415 
.415 
.430 

19.5 
19.5 
19.1 

13 
13 
12 

Average  . 

Nov.  10: 
Standing  .  .  . 

58.8 

54.7 

88.0 

1.19 

1.35 

.420 

19.4 

12 

4.08 

Walking  .  .  . 

48.4 
47.8 
47.1 

2,846 
2,811 
2,769 

84.2 
85.2 
84.8 

.96 
1.03 
1.02 

66.45 
60.56 
59.98 

2.27 
2.32 
2.38 

1.19 
1.24 
1.30 

.418 
.441 
.469 

21.1 
20.4 
21.7 

11 
11 
11 

Average  . 

Nov.  11: 
Standing  .  .  . 
Walking  .  .  . 

58.8 

47.8 

84.7 

1.00 

1.24 

.443 

21.1 

11 

4.08 

67.1 
68.2 
68.4 

3,952 
4,017 
4,029 

99.0 
98.8 
99.2 

2.37 
2.61 
2.39 

139.59 
153.73 
140.77 

2.78 
2.96 
2.93 

1.70 

1.88 
1.85 

.430 
.468 
.459 

12.2 
12.2 
13.1 

19 
19 

18 

Average  . 

Nov.  12: 
Standing  .  .  . 

58.9 

67.9 

99.0 

2.46 

1.81 

.452 

12.5 

19 

4.08 

Walking  .  .  . 

66.0 
67.7 
67.6 

3,881 
3,981 
3,975 

99.2 
99.4 
98.8 

1.84 
1.95 
1.96 

108.19 
114.66 
115.25 

2.84 
2.91 
2.92 

1.76 
1.83 
1.84 

.453 
.460 
.463 

16.3 
16.0 
16.0 

14 
15 
15 

Average  . 

58.8 

67.1 

99.1 

1.92 



1.81 

.459 

16.1 

15 

1Average  of  values  obtained  in  experiments  without  food,  with  subjects  standing,  October  11  to  December  22, 
1915,  inclusive.     (See  table  6,  page  46.) 


132 


METABOLISM   DURING   WALKING. 


TABLE  32. — Increase  in  heat-output  of  E.  D.  B.  during  horizontal  walking  in  experiments  without  food. 

(Values  per  minute.) — Continued. 


Date 
and 
condition. 

(a) 

Body- 
weighi 
with 
cloth- 
ing. 

Dis- 
tance. 

(e) 

Hori- 
zontal 
kilo- 
gram- 
meters. 

a  X  b 

to 

No.  of 

steps. 

(e) 

Rais- 
ing of 
body 
(step- 
lift). 

Work 
due  to 
step- 
lift. 

a  X  e 

Total 
heat. 

Increment  in  heat  above  standing- 
value. 

00 

Total 
in- 
crease. 

(t) 
Per  hori- 
zontal 
kilo- 
gram- 
meter. 

hX  1,000 

Per  kilo- 
gram- 
meter 
of  step- 
lift. 

hX  1,000 

(AO 
Propor- 
tion   of 
increase 
due   to 
step-lift. 

2.34X100 

c 

/ 

3 

1915. 
Nov.  13: 
Standing 

kg. 

meters. 

meters 

kg.  m. 

cals. 
"1.  08 

cals. 

gm.-cal. 

gm.-cah 

p.  ct. 

Walking  .  .  . 

76.1 
76.9 
77.0 

4,467 
4,514 
4,520 

104.2 
103.2 
104.4 

2.61 
2.96 
2.67 

153.21 
173.75 
156.73 

3.04 
3.23 
3.11 

1.96 
2.15 
2.03 

0.439 
.476 
.449 

12.8 
12.4 
12.3 

18 
19 
19 

Average  . 

Nov.  15: 
Standing  .  .  . 

58.7 

76.7 

103.9 

2.75 

2.05 

.455 

12.5 

19 

'1.08 

Walking.  .  . 

76.3 
77.1 
77.5 

4,525 
4,572 
4,596 

103.0 
104.6 
104.4 

2.80 
2.93 
2.77 

166.04 
173.75 
164.26 

3.15 
3.21 
3.18 

2.07 
2.13 
2.10 

.457 
.466 
.457 

12.5 
12.3 
12.8 

19 
19 

18 

Average  . 

Nov.  16: 
Standing.  .  . 

59.3 

77.0 

104.0 

2.83 

2.10 

.460 

12.5 

19 

n  os 

Walking.  .  . 

76.4 
77.0 
77.4 

4,485 
4,520 
4,543 

102.8 
104.2 
104.1 

2.92 
2.81 
2.97 

171.40 
164.95 
174.34 

3.19 
3.17 
3.17 

2.11 
2.09 
2.09 

.470 
.462 
.460 

12.3 
12.7 
12.0 

19 
18 
20 

Average  . 

Nov.  17: 
Standing.  .  . 

58.7 

76.9 

103.7 

2.90 

2.10 

.464 

12.3 

19 

ll  08 

Walking.  .  . 

46.2 
45.4 
45.6 

2,707 
2,660 
2,672 

79.0 
79.0 
79.0 

.86 
.75 
.74 

50.40 
43.95 
43.36 

2.29 
2.28 
2.30 

1.21 
1.20 
1.22 

.447 
.451 
.457 

24.0 
27.3 
28.1 

10 

9 

8 

Average  . 

Nov.  18: 
Standing.  .  . 

58.6 

45.7 

79.0 

78 

1.21 

.452 

26.5 

9 

1  01 

Walking... 

55.7 
54.9 
54.6 
54.9 
54.7 

3,253 
3,206 
3,189 
3,206 
3,194 

90.8 
87.4 
87.4 
88.0 
87.8 

1.32 
1.27 
1.21 
1.10 
1.15 

77.09 
74.17 
70.66 
64.24 
67.16 

2.46 
2.39 
2.47 
2.50 
2.51 

1.45 
1.38 
1.46 
1.49 
1.50 

.446 
.430 

.458 
.465 
.470 

18.8 
18.6 
20.6 
23.2 
22.3 

12 
13 
11 
10 
11 

Average  . 

Nov.  19: 
Standing  .  .  . 

58.4 

55.0 

88.3 

1.21 

1.46 

.454 

20.7 

11 

1  02 

Walking.  . 

76.5 

77.7 
77.9 
78.4 
78.9 

4,468 
4,538 
4,549 
4,579 
4,608 

104.8 
104.3 
103.0 
104.6 
104.0 

2.44 
2.49 
2.47 
2.46 
2.31 

142.50 
145.42 
144.25 
143.66 
134.90 

3.06 
3.24 
3.19 
3.22 
3.25 

2.04 
2.22 
2.17 
2.20 
2.23 

.457 
.489 
.477 
.480 
.484 

14.3 
15.3 
15.0 
15.3 
16.5 

16 
15 
16 
15 

14 

Average  . 

58.4 

77.9 

104.1 

2.43 

2.17 

.477 

15.3 

15 

1  Average  of  values  obtained  in  experiments  without  food,  with  subjects  standing,  October  11  to  December  22, 
1915,  inclusive.     (See  table  6,  p.  46.) 


EXPERIMENTS   WITH   HORIZONTAL   WALKING. 


133 


TABLE  32. — Increase  in  heat-output  of  E.  D.  B.  during  horizontal  walking  in  experiment*  without  food. 

(Values  per  minute.) — Continued. 


Date 
and 
condition. 

(a) 

Body- 
weight 
with 
cloth- 
ing. 

(&) 

Dis- 
tance. 

(c) 

Hori- 
zontal 
kilo- 
gram- 
meters. 

0X6 

(d) 

No.  of 

steps. 

(«) 

Rais- 
ing of 
body 
(step- 
lift). 

(/) 

Work 
due  to 
step- 
lift. 

o  X  e 

(ff) 

Total 
heat. 

Increment  in  heat  above  standing- 
value. 

(*) 

Total 
in- 
crease 

« 

Per  hori- 
zontal 
kilo- 
gram- 
meter. 

AXI.OOO 

0") 
Per  kilo- 
gram- 
meter 
of  step- 
lift. 

hX  1,000 

(*) 
Propor- 
tion of 
increase 
due  to 
step-lift. 

2.34X100 

c 

/ 

J 

1915. 
Nov.  22: 

kg. 

meters. 

meters. 

kg.  m. 

cals. 
ll.Q8 

cats. 

gm.-cal. 

gm.-caU. 

p.  ct. 

48.0 
47.3 
46.8 

2,798 
2,758 
2,728 

82.2 
80.2 
79.8 

.79 

46.06 

2.37 
2.37 
2.32 

1.29 
1.29 
1.24 

0.461 
.468 
.455 

28.0 

8 

Average  . 
Nov.  23: 

.79 

46.06 

26.9 

9 

58.3 

47.4 

80  7 

79 

1.27 

.461 

27.5 

9 

• 

n.os 

Walking 

55.5 
53.9 
54.9 

3,275 
3,180 
3,239 

89.2 
86.2 
87.8 

1.18 
1.34 
1.26 

69.62 
79.06 
74.34 

2.42 
2.41 
2.43 

1.34 
1.33 
1.35 

.409 
.418 
.417 

19.2 
16.8 
18.2 

12 
14 
13 

Average  . 
Nov.  24: 

59.0 

54.8 

87.7 

1  26 

1.34 

.415 

18.1 

13 

»1.08 

Walking 

57.7 
57.6 
57.1 

3,399 
3,393 
3,363 

90.4 
89.6 
90.0 

1.33 
1.41 
1.37 

78.34 
83.05 
80.69 

2.44 
2.46 
2.47 

1.36 
1.38 
1.39 

.400 
.407 
.413 

17.4 
16.6 
17.2 

13 

14 
14 

Average  . 
Nov.  26: 

58.9 

57.5 

90.0 

1.37 

1.38 

.407 

17.1 

14 

U.OS 

TV  al  king 

65.3 
66.2 
66.2 

3,885 
3,939 
3,939 

98.2 
99.2 
97.6 

1.58 
1.55 
1.84 

94.01 
92.23 
109.48 

2.72 
2.78 
2.78 

1.64 
1.70 
1.70 

.422 
.432 
.432 

17.4 
18.4 
15.5 

13 
13 
15 

Average  . 
Dec.  1: 

59.5 

65.9 

98.3 

1.66 

1.68 

.429 

17.1 

14 

11.08 

\Valking    . 

74.9 
76.4 
77.3 

4,442 
4,531 

4,584 

105.0 
104.8 
106.2 

2.52 
2.71 
2.92 

149.44 
160.70 
173.16 

3.13 
3.24 
3.18 

2.05 
2.16 
2.10 

.462 
.477 
.458 

13.7 
13.4 
12.1 

17 
18 
19 

Average  . 
Dec.  2: 

59.3 

76.2 

105.3 

2.72 

2.10 

.466 

13.1 

18 

4.08 

Walking    . 

71.3 

71.8 
71.8 

4,214 
4,243 
4,243 

101.8 
101.8 
101.8 

2.18 
2.65 
2.63 

128.84 
156.62 
155.43 

2.89 
2.93 
2.87 

1.81 
1.85 
1.79 

.430 
.436 
.422 

14.1 
11.8 
11.5 

17 
20 
20 

Average  . 

59.1 

71.6 

101.8 

2.49 





1.82 

4.29 

12.5 

19 

1  Average  of  values  obtained  in  experiments  without  food,  with  subject  standing,  October  11  to  December  22, 
1915,  inclusive.     (See  table  6,  page  46.) 


134 


METABOLISM   DURING   WALKING. 


TABLE  32. — Increase  in  heat-output  of  E.  D.  B.  during  horizontal  walking  in  experiments  without  food. 

(Values  per  minute?) — Continued. 


Date 
and 
condition. 

(o) 

Body- 
weight 
with 
cloth- 
ing. 

(6) 

Dis- 
tance. 

(c) 

Hori- 
zontal 
kilo- 
gram- 
meters. 

0X6 

(d) 

No.  of 

steps. 

<«) 

Rais- 
ing of 
body 
(step- 
lift). 

(/) 

Work 
due  to 
step- 
lift. 

a  X  « 

(fl) 

Total 
heat. 

Increment  in  heat  above  standing- 
value. 

W 

Total 
in- 
crease. 

CO 

Per  hori- 
zontal 
kilo- 
gram- 
meter. 

h  XI,  000 

0") 
Per  kilo- 
gram- 
meter 
of  step- 
lift. 

h  XI,  000 

(fc) 
Propor- 
tion of 
increase 
due   to 
step-lift. 

2.34X100 

c 

/ 

3 

1915. 
Dec.  3: 

kg. 

meters. 

meters. 

kg.  m. 

cats. 

n.os 

cals. 

gm.-cal. 

gm.-cals. 

p.et. 

Walking  . 

70.5 
71.2 
72.1 

4,188 
4,229 
4,283 

103.2 
101.1 
101.3 

2.39 
2.60 
2.69 

141.97 
154.44 
159.79 

2.95 
2.96 
2.97 

1.87 
1.88 
1.89 

0.447 
.445 
.441 

13.2 
12.1 
11.8 

18 
19 
20 

Average  . 

Dec.  4: 

Standing 

59.4 

71.3 

101.9 

2.56 

1.88 

.444 

12.4 

19 

'1.08 

Walking.  .  . 

47.5 
46.6 
45.9 

2,807 
2,754 
2,713 

79.4 
79.2 

78.4 

.99 
.91 
.89 

58.51 
53.78 
52.60 

2.23 
2.20 
2.24 

1.15 
1.12 
1.16 

.410 
.407 
.428 

19.7 
20.8 
22.1 

12 
11 
11 

Average  . 

Dec.  6: 
Standing 

59.1 

46.7 

79.0 

.93 

1.14 

.415 

20.9 

11 

U.OS 

Walking  . 

45.2 
45.1 

44.7 

2,676 
2,670 
2,646 

78.8 
78.4 
78.2 

.68 
.67 
.68 

40.26 
39.66 
40.26 

2.17 
2.19 
2.16 

1.09 
1.11 
1.08 

.407 
.416 
.408 

27.0 
28.0 
26.8 

9 

8 
9 

Average  . 

Dec.  7: 
Standing.  .  . 

59.2 

45.0 

78.5 

.68 

1.09 

.410 

27.3 

9 

'1.08 

Walking  .  . 

43.8 
43.1 
50.6 

2,593 
2,552 
2,996 

78.8 
77.2 
75.2 

.62 
.54 

.84 

36.70 
31.97 
49.73 

2.24 
2.20 
2.37 

1.16 
1.12 
1.29 

.447 
.439 
.431 

31.6 
35.0 
26.0 

7 
7 
9 

Average  . 

Dec.  13: 

Standing  .  .  . 

59.2 

45.8 

77.1 

.67 

1.19 

.439 

30.9 

8 

U.OS 

Walking  .  .  . 

66.8 
66.6 
66.7 

3,834 
3,823 
3,829 

98.6 
97.8 
96.4 

1.84 
2.27 
2.09 

105.62 
130.30 
119.97 

2.63 
2.81 
2.68 

1.55 
1.73 
1.60 

.404 
.453 
.418 

14.7 
13.3 
13.3 

16 

18 
18 

Average  . 

1916. 
Jan.  31  : 
Standing.  .  . 

57.4 

66.7 

97.6 

2.07 

1.63 

.425 

13.8 

17 

1  16 

Walking  .  .  . 

62.0 
63.5 
63.4 
63.9 

3,825 
3,918 
3,912 
3,943 

99.0 
97.0 
94.4 
93.4 

2.21 
2.59 
2.59 
2.59 

136.36 
159.80 
159.80 
159.80 

3.20 
3.22 
3.29 
3.22 

2.04 
2.06 
2.13 
2.06 

.533 
.526 
.544 
.522 

15.0 
12.9 
13.3 
12.9 

16 
18 

18 
18 

Average  . 

61.7 

63.2 

96.0 

2.50 



2.07 

.531 

18.0 

17 

1  Average  of  values  obtained  in  experiments  without  food,  with  subject  standing,  October  11  to  December  22, 
1915,  inclusive.     (See  table  6,  page  46.) 


EXPERIMENTS  WITH   HORIZONTAL   WALKING. 


135 


TABLE  32  — Increase  in  heat-output  of  E.  D.  B.  during  horizontal  walking  in  experiments  without  food. 

(Values  per  minute.) — Continued. 


Date 
and 
condition. 

(a) 

Body 
weigl 
with 
cloth 
ing. 

(6) 

Dis- 
tance 

(c) 

Hori- 

zonta 
kilo- 
gram- 
meters 

a  X  & 

(<*) 

No.  o 
steps. 

(e) 

Rais- 
ing o 
body 
(step 
lift). 

(/) 

Work 
due  to 
step- 
lift. 

o  X   e 

<ff) 

Total 
heat 

Increment  in  heat  above  standing- 
value. 

W 

Total 
in- 
crease 

« 
Per  hon 
zontal 
kilo- 
gram- 
meter. 

AX  1,00 

CO 
Per  kilo- 
gram- 
meter 
of  step- 
lift. 

hX  1,00 

(*) 
Propor- 
tion of 
increase 
due   to 
step-lift. 

2.34X100 

c 

/ 

i 

1916. 
Feb.  1  : 
Standing 

kg. 

meters 

meters 

kg.  m. 

cols. 
1.29 

cals. 

gm.-cal 

gm.-cals 

p.ct. 

Walking  .  . 

Average 

Mar.  20: 
Standing 

62.9 
63.2 
64.3 
63.9 

3,906 
3,925 
3,993 
3,968 

93.4 
94.4 
94.8 
94.0 

2.24 
2.28 
2.10 
2.28 

139.10 
141.59 
130.41 
141.59 

3.19 
3.09 
2.95 
3.11 

1.90 
1.80 
1.66 
1.82 

0.486 
.459 
.416 
.459 

13.6 
12.7 
12.7 
12.8 

17 
18 
18 
18 

62.1 

63.6 

94.2 

2.23 

1.80 

.455 

13.0 

18 

1.29 

Walking  .  . 

Average  . 

Mar.  22: 

Standing  .  . 

59.5 
60.7 

3,647 
3,721 

2.94 
2.85 

1.65 
1.56 

.452 
.419 

61.3 

60.1 

1.61 

.436 

1.22 

Walking.  .  . 

Average  . 

Mar.  29: 

Standing 

74.8 
76.9 

4,563 
4,691 

3.32 
3.40 

2.10 
2.18 

.460 
.465 

61.0 

75.9 

2.14 

.463 

1.26 

Walking 

57.6 
55.5 

3,502 
3,374 

2.89 
2.85 

1.63 
1.59 

.465 
.471 

Average  . 

Mar.  30: 
Standing 

60.8 

56.6 

1.61 

.468 

1.19 

Walking 

68.5 
63.6 

4,192 
3,892 

3.32 
3.02 

2.13 
1.83 

.508 
.470 

Average  . 

Mar.  31: 

Standing 

61.2 

66.1 

1.98 

.489 

1.19 

55.2 
52.9 

3,356 
3,216 

2.69 
2.73 

1.50 
1.54 

.447 
.479 

Average  . 

60.8 

54.1 

1.52 

.463 

Apr.  1: 

1.15 

Walking 

53.4 
51.7 
50.4 

3,257 
3,154 
3,074 

2.67 
2.61 
2.59 

1.52 
1.46 
1.44 

.467 
.463 
.468 

Average  . 

61.0 

51.8 

1.47 

.466 

136 


METABOLISM   DURING   WALKING. 


TABLE  32. — Increase  in  heat-output  of  E.  D.  B.  during  horizontal  walking  in  experiments  without  food. 

(Values  per  minute.') — Continued. 


Date 
and 
condition. 

(a) 

3ody- 
weight 
with 
cloth- 
ing. 

(« 

Dis- 
tance. 

(e) 

Hori- 
zontal 
kilo- 
gram- 
meters. 

o  X  b 

M) 

No.  of 

steps. 

(«) 

Rais- 
ing of 
body 
(step- 
lift). 

(/) 

Work 
due  to 
step- 
lift. 

a  X  e 

(a) 

Total 
heat. 

Increment  in  heat  above  standing- 
value. 

W 

Total 
in- 
crease. 

« 

Per  hori- 
zontal 
kilo- 
gram- 
meter. 

h  XI,  000 

(;•) 
Per  kilo- 
gram- 
meter 
of  step- 
lift. 

AX  1,000 

(k) 
Propor- 
tion of 
increase 
due   to 
step-lift. 

2.34  X  100 

c 

/ 

j 

1916. 
Apr.  3: 

kg. 

meters. 

meters. 

kg.  m. 

cats. 
1  19 

cals. 

gm.-cal. 

gm.-cala. 

p.ct. 

Walking.  .  . 

35.1 
35.7 
36.7 

2,152 

2,188 
2,250 

2.18 
2.27 
2.25 

.99 
1.08 
1.06 

0.460 
.494 
.471 

Average  . 

Apr.  4: 
Standing  .  .  . 

61.3 

35.8 

1.04 

.475 

1.13 

Walking  .  .  . 

35.9 
37.0 
37.0 

2,183 
2,250 
2,250 

2.30 
2.25 
2.33 

1.17 
1.12 
1.20 

.536 
.498 
.533 

Average  . 

Apr.  5: 
Standing.  .  . 

60.8 

36.6 

1.16 

.522 

1.18 

Walking  .  .  . 

77.4 
76.5 
79.3 

4,714 
4,659 
4,829 

3.53 
3.42 
3.51 

2.35 
2.24 
2.33 

.499 
.481 
.483 

Average  . 

Apr.  10: 
Standing  .  .  . 

60.9 

77.7 

2.31 

.488 

l.lfr 

Walking  .  .  . 

Average  . 

Apr.  11: 

Standing  .  .  . 

78.7 
77.1 

4,832 
4,734 

3.59 
3.56 

2.43 
2.40 

.503 
.507 

61.4 

77.9 

2.42 

.505 

1.16 

Walking  .  .  . 

Average  . 

Apr.  12: 
Standing  .  .  . 

95.9 
92.0 
89.0 

5,840 
5,603 
5,420 







4.47 
4.14 
4.10 

3.31 
2.98 
2.94 

.567 
.532 
.542 

60.9 

92.3 

3.08 

.547 

1.21 

Walking  .  .  . 

89.2 
89.0 
86.6 

5,423 
5,411 
5,265 

4.34 
4.18 
4.04 

3.13 
2.97 
2.83 

.577 
.549 
.538 

Average 

Apr.  13: 
Standing  .  . 

60.8 

88.3 

2.98 

.555 

1.17 

Walking.  . 
Average 

99.7 
97.7 
94.9 

6,072 
5,950 
5,779 

4.55 
4.59 
4.29 

3.38 
3.42 
3.12 

.557 
.575 
.540 

60.9 

97.4 

3.31 

.557 

EXPERIMENTS  WITH   HORIZONTAL   WALKING. 


137 


TABLE  33.— Increase  in  heat-output  of  J.  H.  (?.,  E.  L.  F.,  and  H.  M.  S.  during  horizontal  walking  in 
experiments  without  food.     (Values  per  minute.) 


Date 
and 
condition. 

(a) 

Body- 
weight 
with 
cloth- 
ing. 

(&) 

Dis- 
tance. 

(c) 

Hori- 
zontal 
kilo- 
gram- 
meters. 

a  X  & 

(<*) 

No.  of 

steps. 

(e) 

Rais- 
ing of 
body 
(step- 
lift). 

(/) 

Work 
due  to 
step- 
lift. 

a  X  e 

(0) 

Total 
heat. 

Increment  in  heat  above  standing- 
value. 

w 

Total 
in- 
crease. 

(0 
Per  hori- 
zontal 
kilo- 
gram- 
meter. 

h  XI,  000 

0') 
Per  kilo- 
gram- 
meter 
of  step- 
lift. 

A  XI,  000 

« 
Propor- 
tion of 
increase 
due   to 
step-lift. 

2.34X100 

c 

/ 

i 

J.  H.  G. 
1916 
Jan.  18; 

Standing  .  .  . 
Walking.  .  . 

Average  . 
Jan.  19: 

kg. 

meters. 

meters. 

kg.  m. 

cola. 
1.39 

cats. 

gm.-cal. 

gm.-cals. 

p.  ct. 

55.3 
55.2 
54.5 

3,832 
3,825 
3,777 

83.8 
90.6 
90.0 

1.05 
1.37 
1.52 

72.  S 
94.9 
105.3 

3.55 
3.45 
3.39 

2.16 
2.06 
2.00 

0.564 
.539 
.530 

29.7 
21.7 
19.0 

8 
11 
12 

69.3 

55.0 

88.1 

1.31 

2.07 

.544 

23.5 

10 

1.29 

55.3 
55.1 
53.8 

3,821 
3,807 
3,718 

88.9 
105.2 
108.8 

1.71 
1.71 
1.54 

118.2 
118.2 
106.4 

3.31 
3.42 
3.31 

2.02 
2.13 
2.02 

.529 
.559 
.543 

17.1 
18.9 
19.0 

14 
12 
12 

Average  . 
Jan.  20: 

69.1 

54.7 

101.0 

1.65 

2.06 

.544 

18.3 

13 

1.33 

55.9 
55.6 
53.5 

3,930 
3,909 
3,761 

89.7 
96.2 
105.4 

1.70 
1.76 
1.67 

119.5 
123.7 
117.4 

3.33 
3.33 
3.26 

2.00 
2.00 
1.93 

.509 
.512 
.513 

16.7 
16.2 
16.4 

14 
14 
14 

Average  . 

E.  L.  F. 
Jan.  21  : 

70.3 

55.0 

97.1 

1.71 

1.98 

.511 

16.4 

14 

1.36 

Walking 

52.5 
52.3 
52.5 

3,801 
3,787 
3,801 

90.6 
90.4 
89.8 

1.71 
1.80 
1.84 

123.8 
130.3 
133.2 

3.85 
3.39 
3.40 

2.49 
2.03 
2.04 

.655 
.536 
.537 

20.1 
15.6 
15.3 

12 
15 
15 

Average  . 
Jan.  22: 

72.4 

52.4 

90.3 

1.78 

2.19 

.576 

17.0 

14 

1.26 

Walking    . 

53.6 
52.5 
52.3 

3,945 
3,864 
3,849 

96.6 
93.2 

1.98 
1.59 

145.7 
117.0 

3.39 
3.40 
3.33 

2.13 
2.14 
2.07 

.540 
.554 
.538 

14.6 
18.3 

16 

13 

Average 

73.6 

52.8 

94.9 

1.79 



2.11 

.544 

16.5 

14 

138 


METABOLISM   DURING   WALKING. 


TABLE  33. — Increase  in  heat-output  of  J.  H.  G.,  E.  L.  F.  and  H.  M.  S.  during  horizontal  walking  in 
experiments  without  food.     (Values  per  minute.) — Continued. 


Date 
and 
condition. 

(a) 

Body- 
weigh  i 
with 
cloth- 
ing. 

(b) 

Dis- 
tance. 

(c) 

Hori- 
zontal 
kilo- 
gram- 
meters. 

a  X  b 

(d) 

No.  of 

steps. 

<«> 

Rais- 
ing of 
body 
(step- 
lift). 

CO 

Work 
due  to 
step- 
lift. 

o  X  e 

(a) 

Total 
heat. 

Increment  in  heat  above  standing- 
value. 

W 

Total 
in- 
crease 

(t) 
Per  hori- 
zontal 
kilo- 
gram- 
meter. 

Axl.OOO 

U) 
Per  kilo- 
gram- 
meter 
of  step- 
lift. 

h  XI,  000 

<*> 
Propor- 
tion of 
increase 
due  to 
step-lift. 

2.34  X100 

c 

/ 

i 

E.  L.  F.  (Cont.) 
Jan.  24: 

Standing.    . 

kg. 

meters. 

meters. 

kg.    m. 

cols. 
1.24 

cals. 

gm.-cal. 

gm.-cals. 

p.  ct. 

Walking  .  . 

49.6 
49.2 

48.4 

3,576 
3,547 
3,490 

95.9 
100.8 
90.4 

1.58 
1.64 
1.61 

113.9 
118.2 
116.1 

3.28 
3.24 
3.21 

2.04 
2.00 
1.97 

0.570 
.564 
.564 

17.9 
16.9 
17.0 

13 

14 
14 

Average  . 

H.  M.  S. 
Jan.  25: 

Standing  . 

72.1 

49.1 

95.7 

1.61 

2.00 

.566 

17.3 

14 

1  13 

Walking.  .  . 

44.6 
42.2 
41.6 

2,944 
2,785 
2,746 

79.2 
76.2 
76.0 

1.74 
1.68 
1.70 

114.8 
110.9 
110.2 

2.97 
2.78 
2.79 

1.84 
1.65 
1.66 

.625 
.592 
.605 

16.0 
14.9 
15.1 

15 
16 
16 

Average  . 

Jan.  26: 

Standing  .  .  . 

66.0 

42.8 

77.1 

1.71 

1.72 

.607 

15.3 

15 

1.12 

Walking  .  .  . 

53.5 
52.7 
52.3 

3,520 
3,468 
3,441 

90.4 
77.2 
83.2 

2.36 
2.34 
2.37 

155.3 
154.0 
155.9 

3.18 
3.07 
3.04  . 

2.06 
1.95 
1.92 

.585 
.562 
.558 

13.3 
12.7 
12.3 

18 
18 
19 

Average  . 

65.8 

52.8 

83.6 

2.36 

1.98 

.568 

12.8 

18 

In  considering  the  data  in  tables  29  to  33  for  the  increment  over  the 
standing  requirement,  it  should  be  remembered  that,  as  explained  on 
page  94,  the  standing  metabolism  was  not  obtained  on  each  day  that 
walking  experiments  were  performed  and  whenever  this  was  the  case, 
an  average  value,  or  a  value  determined  from  a  series  of  days  nearest 
the  time  of  the  walking  experiments,  has  been  used.  The  selection  of 
the  standing  values  to  be  used  on  those  days  for  which  it  was  not  de- 
termined has  been  a  matter  of  some  difficulty.  Thus,  H.  R.  R.  on 
March  20  showed  an  unusually  high  standing  metabolism.  This 
value  has  been  employed  in  computing  the  increase  for  walking  on  that 
day,  but  it  has  been  considered  that  probably  the  measurements  found 
on  April  10  and  17  more  nearly  represent  the  normal  basal  metabolism 
for  this  man,  and  the  average  for  these  two  days  has  been  used  in 


EXPERIMENTS  WITH   HORIZONTAL   WALKING.  139 

computing  the  increase  on  March  27,  April  3,  and  24,  on  which  there 
were  no  standing  experiments. 

TOTAL  INCREMENT  IN  HEAT-PRODUCTION. 

The  total  increment  in  the  heat-production  above  the  standing 
requirement  is  assumed  to  represent  the  energy  cost  of  the  transporta- 
tion of  the  body-weight  over  a  definite  distance  on  the  level  as  expressed 
in  horizontal  kilpgrammeters.  As  the  amount  of  this  total  increment 
naturally  depends  upon  the  speed  of  walking,  the  values  in  column  h 
are  of  but  minor  interest  here,  especially  as  theoretically  no  work  is 
done  hi  this  process  and  no  efficiency  value  can  be  computed.  It  may 
be  noted,  however,  that  for  moderate  rates  of  walking,  i.  e.,  50  to 
60  meters  per  minute  (approximately  2  miles  an  hour),  the  total  in- 
crease for  most  of  the  subjects  is  a  little  less  than  double  the  standing 
requirement,  with  W.  K.  an  apparent  exception.  E.  D.  B.  shows  for 
speeds  of  95  to  100  meters  per  minute  (approximately  4  miles  an  hour), 
an  increase  of  nearly  three  times  his  requirement  when  he  was  stand- 
ing, while  for  a  speed  of  35  meters  per  minute  the  increase  was  about 
the  same  as  for  the  standing  requirement,  or,  stated  in  another  way, 
when  the  walking  was  done  at  a  rate  of  35  meters  per  minute,  only  half 
of  the  total  energy  expended  was  due  to  the  act  of  walking. 

INCREMENT  IN  HEAT  PER  HORIZONTAL  KILOGRAMMETER. 

The  main  point  of  interest  in  tables  29  to  33  is  the  increment  in  the 
heat  per  horizontal  kilogrammeter,  as  this  shows  the  energy  cost  of 
walking  1  horizontal  meter.  This  is  later  used  to  represent  the  hori- 
zontal component  in  the  energy  cost  of  grade  walking.  These  values 
are  given  in  column  i  of  the  several  tables. 

For  A.  J.  O.,  at  a  speed  of  approximately  63  meters  per  minute,  the 
walking  was  done  at  a  cost  of  from  0.416  to  0.501  gram-calorie  per 
horizontal  kilogrammeter,  with  an  average  value  for  the  three  days  of 
0.454  gram-calorie.  (See  table  29.) 

The  data  for  H.  R.  R.  show  a  range  in  the  average  values  for  cost 
per  horizontal  kilogrammeter  from  0.643  gram-calorie  on  the  first  day 
to  0.574  gram-calorie  on  the  last  day.  The  first  period  of  the  first 
day  (March  20)  was  marked  by  the  fact  that  the  largest  energy  cost 
for  this  subject  was  here  found.  As  noted  in  the  discussion  of  table  3, 
the  highest  standing  metabolism  for  this  subject  was  also  found  on  this 
day.  In  spite  of  this  high  standing  metabolism,  the  increase  for  the 
horizontal  walking  is  greater  than  on  the  subsequent  days.  On  the  last 
two  days  of  experimenting,  H.  R.  R.  seems  to  have  walked  at  a  less 
cost  per  horizontal  kilogrammeter,  but  the  data  are  too  limited  for  the 
drawing  of  any  conclusions  as  to  the  real  betterment  in  this  man's 
ability  to  walk  with  a  smaller  energy  outlay  as  the  time  progressed. 

T.  H.  H.,  walking  at  a  rate  varying  between  63  and  68  meters  per 
minute,  had  an  increase  in  the  energy  output  per  horizontal  kilogram- 


140  METABOLISM    DURING   WALKING. 

meter  ranging  between  0.512  gram-calorie  on  February  25  and  0.637 
gram-calorie  on  April  5.  The  average  increment  on  this  basis  for  the 
7  days  was  0.579  gram-calorie.  The  daily  average  increase  per  hori- 
zontal kilogrammeter  shows,  if  anything,  a  tendency  to  increase  on  the 
last  2  days,  when  the  walking  was  done  at  a  somewhat  slower  speed. 
The  energy  cost  for  consecutive  periods  shows  no  trend  in  any  one 
direction.  It  can  hardly  be  said  that  the  subject  walked  regularly 
enough  to  develop  any  training  effect,  though  it  is  to  be  assumed  that 
acquaintance  with  the  routine  might  have  reduced  any  psychical  effect 
or  feeling  of  novelty. 

Of  the  15  days  during  which  W.  K.  walked  on  a  level  (see  table  31), 
13  days  were  in  March,  at  the  beginning  of  his  use  as  a  subject.  Since 
there  were  no  extreme  differences  in  the  speed  of  walking,  the  range 
being  from  58  to  68  meters  per  minute  on  these  days,  they  offer  a 
fairly  consecutive  record  from  which  comparisons  may  be  expected. 
The  range  in  the  daily  cost  per  horizontal  kilogrammeter  during  March 
is  from  0.574  gram-calorie  on  March  4  to  0.440  gram-calorie  on  March 
31.  (See  table  31.)  This  decrease  in  the  cost  might  be  taken  to  indi- 
cate an  improvement  but  for  the  fact  that  the  change  is  very  irregular, 
although  as  a  rule  the  higher  values  are  found  in  the  first  days  of  the 
month.  Thus,  the  average  for  the  first  7  days  of  experimenting  in 
March  is  0.516  gram-calorie  and  for  the  last  6  days  it  is  0.480  gram- 
calorie  per  horizontal  kilogrammeter.  It  should  also  be  noted  that 
the  last  day  on  which  W.  K.  was  a  subject  (June  23),  after  4  months  of 
almost  daily  walking  (see  also  table  15),  his  average  cost  per  horizontal 
kilogrammeter  was  lower  than  that  on  any  other  day,  namely,  0.409 
gram-calorie.  The  results  of  the  series  might  be  taken  to  indicate, 
on  the  whole,  a  decrease  in  the  cost  per -horizontal  kilogrammeter  as 
this  man  continued  his  experiments.  The  average  for  the  entire  series 
of  horizontal  walking  experiments  with  W.  K.  shows  an  expenditure 
over  that  for  standing  of  0.490  gram-calorie  per  horizontal  kilogram- 
meter. 

In  the  case  of  E.  D.  B.  the  energy  cost  per  horizontal  kilogrammeter 
ranged  from  0.603  gram-calorie  on  October  9,  the  first  day  of  his  walk- 
ing, to  as  low  as  0.407  gram-calorie  on  November  24,  while  the  average 
for  the  total  61  days  is  0.478  gram-calorie.  (See  table  32.)  To 
study  the  effect  of  training,  the  values  for  the  same  speeds  have  been 
grouped  chronologically  in  table  34,  so  that  the  results  for  the  different 
days  will  be  comparable.  The  daily  averages  for  both  the  total  heat- 
output  and  the  increment  per  horizontal  kilogrammeter  are  given  in 
this  table.  For  the  approximate  speed  of  55  meters  per  minute,  the 
speed  at  which  E.  D.  B.  first  walked,  the  cost  per  horizontal  kilogram- 
meter  fell  quite  consistently  from  0.603  gram-calorie  on  October  9 
to  0.407  gram-calorie  on  November  24.  For  a  speed  of  65  meters  per 
minute  there  is  also  a  fall  between  October  16  and  December  13, 


EXPERIMENTS  WITH   HORIZONTAL  WALKING. 


141 


though  the  change  is  not  so  great  as  with  55  meters  per  minute.  The 
experiments  at  the  speed  of  77  meters  per  minute  were  first  made  late 
in  October,  and  the  effect  of  the  training  had  already  taken  place  to 
some  extent.  Moreover,  at  this  speed,  the  subject  was  approaching 

TABLE  34. — Daily  values  for  metabolism  of  E.  D.  B.,  grouped  chronologically  on  the  basis  of 
speed,  to  determine  effect  of  training.     (Values  per  minute.) 


In- 

In- 

In- 

Approxi- 
mate speed 
and  date. 

Total 
heat- 
out- 
put. 

crease 
in  heat 
per 
hori- 
zontal 

Approxi- 
mate speed 
and  date. 

Total 
heat- 
out- 
put. 

crease 
in  heat 
per 
hori- 
zontal 

Approxi- 
mate speed 
and  date. 

Total 
heat- 
out- 
put. 

crease 
in  heat 
per 
hori- 
zontal 

kg.  m. 

kg.  m. 

kg.  m. 

37  meters: 

cols. 

gm.  cal. 

55  meters  — 

cols. 

gm.  cal. 

72  meters: 

calf. 

gm.  cal. 

Apr.     3 

2.23 

0.475 

(cont.). 

Oct.   22 

3.18 

0.494 

4 

2.29 

.522 

Nov.  8 

2.57 

.451 

23 

3.23 

.503 

45  meters: 

9 

2.43 

.420 

25 

3.22 

.497 

Oct.   30 

2.36 

.496 

18- 

2.47 

.454 

26 

3.20 

.503 

Nov.    1 

2.32 

.474 

23 

2.42 

.415 

Dec.     2 

2.90 

.429 

2 

2.32 

.489 

24 

2.45 

.407 

3 

2.96 

.444 

3 

2.26 

.450 

Mar.  29 

2.88 

.468 

77  meters: 

5 

2.32 

.460 

31 

2.71 

.463 

Oct.   27 

3.34 

.498 

6 

2.25 

.435 

Apr.     1 

2.62 

.466 

28 

3.30 

.487 

10 

2.32 

.443 

65  meters: 

29 

3.39 

.501 

17 

2.29 

.452 

Oct.   16 

3.01 

.510 

Nov.  13 

3.12 

.455 

22 

2.35 

.461 

18 

2.96 

.483 

15 

3.18 

.460 

Dec.     4 

2.21 

.415 

19 

3.05 

.503 

16 

3.17 

.464 

6 

2.18 

.410 

20 

3.09 

.517 

19 

3.20 

.477 

7 

2.27 

.439 

21 

3.07 

.517 

Dec.     1 

3.19 

.466 

55  meters: 

Nov.  11 

2.89 

.452 

Mar.  22 

3.36 

.463 

Oct.     9 

3.26 

.603 

12 

2.89 

.459 

Apr.     5 

3.48 

.488 

11 

2.99 

.559 

26 

2.76 

.429 

10 

3.57 

.505 

13 

2.93 

.539 

Dec.  13 

2.70 

.425 

91  meters: 

14 

2.85 

.527 

'Jan.   31 

3.23 

.531 

Apr.   11 

4.24 

.547 

15 

2.84 

.543 

'Feb.     1 

3.08 

.455 

12 

4.19 

.555 

Nov.    4 

2.48 

0.447 

Mar.  20 

2.89 

.436 

13 

4.48 

.557 

30 

3.17 

.489 

'After  recess  of  3  weeks. 

the  point  which  Durig  has  termed  "the  maximal  efficiency  speed," 
above  which  the  energy  cost  increases  in  a  faster  ratio.  In  spite  of 
these  neutralizing  factors,  there  is  evidence  of  a  fall  in  the  energy  cost 
between  the  end  of  October  and  the  middle  of  November.  The  speed 
of  45  meters  per  minute  was  not  used  until  October  30,  but  even  these 
values  indicate  a  decrease  in  the  latter  part  of  the  series.  It  seems 
clear,  therefore,  that  in  the  early  horizontal-walking  experiments  with 
E.  D.  B.,  lack  of  practice  or  training  was  a  factor  in  the  energy  require- 
ment. In  this  connection  it  should  be  noted  that  on  January  31,  on 
E.  D.  B.'s  return  from  a  three  weeks'  recess  due  to  a  lame  foot,  he  had 
a  much  higher  energy  cost  per  horizontal  kilogrammeter  than  at  the 
end  of  his  previous  walking  experiments.  This  may  be  an  erratic 
result,  for  it  may  also  be  noted  that  on  the  second  day  following 


142  METABOLISM   DURING   WALKING. 

the  energy  expenditure,  though  slightly  above  the  average,  was  not  in 
any  way  exceptional. 

From  these  considerations  it  may  be  seen  that  the  value  of  0.478 
gram-calorie,  while  representing  an  average  figure  for  this  subject  for 
the  61  days,  does  not  show  the  energy  cost  for  a  trained  subject.  If 
we  take  the  values  found  for  December  and  March,  and  thereby  elimi- 
nate the  influence  of  the  early  data  and  also  the  extremely  high  and 
low  speeds  of  April,  an  average  value  for  the  energy  cost  is  obtained 
for  E.  D.  B.  of  0.446  gram-calorie.  This  is  much  lower  than  the  aver- 
age value  of  0.55  gram-calorie  reported  by  Benedict  and  Mursch- 
hauser1  in  their  summary  of  the  work  of  earlier  observers.  But  in 
many  cases  these  average  values  for  the  earlier  observers  include 
experiments  performed  when  the  subjects  were  not  in  a  strictly  post- 
absorptive  condition  and  in  a  few  instances  require  an  assumption  of 
the  respiratory  quotient.  Moreover,  different  techniques  were  em- 
ployed in  the  various  researches.  There  is,  therefore,  no  reason  to 
believe  that  the  value  of  0.478  gram-calorie  as  an  average  for  an  un- 
trained subject  over  a  considerable  period  or  of  0.446  gram-calorie  for  a 
trained  subject  is  exceptionally  low. 

This  effect  of  training  finds  support  in  the  figures  from  the  report  of 
Benedict  and  Murschhauser,2  although  the  authors  themselves  do  not 
consider  the  evidence  is  sufficient  to  make  any  conclusion  in  the  matter. 
It  is  seen  from  then-  figures  that  their  Subject  I  had  a  value  of  0.507 
gram-calorie  as  an  average  for  16  experiments  made  during  a  period 
of  1  month.  The  average  for  the  4  last  days  of  this  period,  however, 
was  0.488  gram-calorie  and  for  the  first  5  days  0.515  gram-calorie. 
Also,  then*  Subject  II  in  57  experiments  had  an  average  cost  per  hori- 
zontal kilogrammeter  of  0.493  gram-calorie3  buf  for  the  first  10  days 
of  his  experiments  the  average  value  was  0.506  gram-calorie,  while  for 
the  last  6  days  beginning  with  April  22,  which  was  after  18  days  of 
walking,  the  average  value  was  0.481  gram-calorie.  These  latter 
days,  moreover,  are  when  their  subject  was  walking  at  a  speed  near  the 
point  of  maximal  efficiency. 

It  is  to  be  regretted  that  there  were  no  horizontal-walking  experi- 
ments with  E.  D.  B.  in  the  last  part  of  December  or  the  first  part  of 
January,  when  the  standing  metabolism  of  this  subject  was  found  to 
have  risen  to  a  higher  level.  (See  p.  98.)  But  the  fact  that  the  energy 
cost  per  horizontal  kilogrammeter  for  the  approximate  speeds  of  55  to 
77  meters  per  minute  was  as  a  rule  higher  during  March  or  April  than 
during  the  early  part  of  December  (see  table  34)  indicates  that  the 
increase  in  the  metabolism  shown  by  his  standing  requirements  was 
also  apparent  in  the  cost  per  horizontal  kilogrammeter*. 

'Benedict  and  Murschhauser,  Carnegie  Inst.  Wash.  Pub.  No.  231,  1915,  p.  28. 
'Benedict  and  Murschhauser,  Ibid.,  p.  79. 
'Benedict  and  Murschhauser,  Ibid.,  p.  87. 


EXPERIMENTS   WITH   HORIZONTAL   WALKING.  143 

Of  the  other  three  subjects,  J.  H.  G.  expended  on  an  average  0.533 
gram-calorie  per  horizontal  kilogrammeter,  while  it  cost  E.  L.  F.  0.562 
gram-calorie  and  H.  M.  S.  0.588  gram-calorie  per  horizontal  kilogram- 
meter.  (See  table  33.)  These  men  were  entirely  untrained  and  did 
not  walk  long  enough  in  these  experiments  to  produce  any  training 
effect. 

The  average  cost  per  horizontal  kilogrammeter  of  walking  on  a  level, 
i.  e.,  the  increment  over  the  standing  requirement,  irrespective  of  any 
training  effect  and  at  speeds  mostly  below  80  meters  per  minute,  is  as 
follows  for  each  of  the  eight  men  included  in  this  report :  A.  J.  O.,  0.454; 
H.  R.  R.,  0.618;  T.  H.  H.,  0.579;  W.  K,  0.490;  E.  D.  B.,  0.478;  J.  H.  G., 
0.533;  E.  L.  F.,  0.562;  H.  M.  S.,  0.588  gram-calorie,  with  a  general 
average  of  0.538  gram-calorie.  The  most  data  were  obtained  with 
W.  K.  and  E.  D.  B.,  and  these  men  show  the  lower  values.  A.  J.  O., 
who  likewise  shows  lower  values,  was  also  a  well- trained  subject,  but 
with  him  there  was  only  a  limited  amount  of  data. 

The  average  value  of  0.538  gram-calorie  for  this  group  of  8  men  is 
very  close  to  the  average  value  of  0.55  gram-calorie  quoted  by  Benedict 
and  Murschhauser  in  their  summary  of  the  work  of  other  investi- 
gators previously  referred  to.  Furthermore,  taking  into  considera- 
tion the  fact  that  the  basal  value  used  by  the  other  investigators  was  in 
the  majority  of  cases  either  a  lying  or  a  sitting  value,  the  individual 
values  for  the  8  men  studied  hi  the  present  research  do  not  differ 
widely  in  range  and  character  from  those  given  by  Benedict  and 
Murschhauser1  in  their  summary  of  previous  work  done  on  this  sub- 
ject and  already  referred  to.  Although  the  average  value  for  the 
group  agrees  with  the  average  for  the  subjects  of  other  investigators, 
the  averages  for  the  different  men  show  the  variations  which  may  be 
expected  for  individual  subjects.  That  these  variations  may  be  large 
is  seen  by  comparing  the  average  for  the  trained  subject  E.  D.  B.  and 
the  untrained  but  thoroughly  cooperative  subject  H.  M.  S.,  between 
which  there  is  a  difference  of  nearly  25  per  cent.2 

EFFECT  OF  SPEED  UPON  METABOLISM  IN  HORIZONTAL  WALKING. 

In  order  to  show  more  clearly  the  influence  of  the  speed  of  walking 
upon  the  various  factors  observed,  the  data  in  tables  8  to  12  have  been 
grouped  according  to  certain  arbitrary  limits  of  5  meters  per  minute 
and  averaged.  These  averages  are  given  in  table  35,  which  also  in- 
cludes the  total  increment  and  the  increment  per  horizontal  kilogram- 
meter,  taken  from  columns  h  and  i  of  tables  29  to  33,  grouped  and 
averaged  in  the  same  way.  These  groups  of  data  represent  values 
obtained  in  from  3  to  37  periods,  but  in  most  cases  from  8  to  10  periods 

Benedict  and  Murschhauser,  Carnegie  Inst.  Wash.  Pub.  No.  231,  1915,  pp.  24-27. 
2The  possible  effects  of  weight  and  age  as  factors  in  this  comparison  should  not  be  lost  sight 
of,  since  H.  M.  S.  was  thinner  than  E.  D.  B.,  as  well  as  older  and  taller. 


144 


METABOLISM   DURING   WALKING. 


have  been  averaged.  At  times  consecutive  periods  of  the  same  day 
fall  into  different  groups  if  by  chance  the  speeds  of  the  different 
periods  on  that  day  are  very  near  the  dividing-line.  Each  group 
contains  as  a  rule  the  results  of  several  days  which  were  in  many  cases 
quite  widely  distributed. 

TABLE  35. — Metabolism  during  horizontal  walking  in  experiments  without  food,  grouped 
according  to  speed  of  walking.     (Average  values  per  minute.) 


Subject  and 
speed,  in 
meters. 

No.  of 
periods. 

Average 
distance 
walked. 

No.  of 

steps. 

Hori- 
zontal 
kilo- 
gram- 
meters 
of  work 
done. 

Respira- 
tion- 
rate. 

Pul- 
monary 
venti- 
lation 
(re- 
duced). 

Body- 
tem- 
pera- 
ture. 

Blood- 
pres- 
sure. 

A.  J.  0.: 

60  to  65 

6 

meters. 
63.0 

'96  8 

4,689 

23.8 

liters. 
16.0 

°C. 

mm. 

H.  R.  R.: 

60  to  65 

11 

60.9 

97  1 

4,364 

17.3 

14.8 

65  to  70 

4 

67.1 

103  3 

4,932 

18.0 

16  4 

T.  H.  H.: 
60  to  65 

7 

63  2 

99  6 

3,621 

S14  2 

11  4 

65  to  70 

14 

67  1 

104  1 

3  828 

14  6 

11  4 

W.  K.: 

55  to  60..  . 

10 

58.3 

106  6 

2,999 

21.3 

11.1 

60  to  65  ... 

19 

62.9 

109  8 

3,247 

20  8 

10.8 

65  to  70..  . 

20 

66.6 

114  7 

3  452 

722  4 

11  7 

E.  D.  B.: 
35  to    40.. 

6 

36.2 

2,212 

19.2 

11.3 

36.90 

120 

40  to    45  .. 

13 

43  8 

79  5 

2  578 

18  7 

11  1 

45  to    50.. 

22 

46.3 

80  6 

2,722 

19.5 

11.5 

50  to    55.. 
55  to    60  .. 
60  to    65.. 
65  to    70.. 
70  to    75.. 
75  to    80.. 
85  to    90.. 

22 
18 
30 
15 
26 
37 
4 

53.7 
56.5 
63.9 
66.8 
72.2 
77.5 
88.5 

1087.4 
"89.7 
"96.5 
"98.4 
"101.  6 
"104.7 

3,181 
3,371 
3,840 
3,929 
4,292 
4,584 
5,380 

20.7 
20.0 
19.4 
19.9  " 
19.0 
20.6 
24.1 

13.3 
14.5 
14.2 
14.0 
13.9 
15.1 
18.5 

437.03 
436.84 
'37.18 
U37.13 
1436.90 
337.12 
37.25 

4125 
4124 
17120 
14119 
14122 
3125 
130 

90  to  100.. 

5 

96.0 

5,849 

23.9 

20.1 

37.28 

130 

J.  H.G.: 
50  to  55..  . 

3 

53.9 

101  4 

19  4 

16  1 

55  to  60.  .  . 

6 

55  4 

92  3 

18  7 

15  5 

E.  L.  F.: 
45  to  50..  . 

3 

49  1 

95  7 

5  4 

13  6 

50  to  55  ... 

6 

52  6 

*92  1 

12  3 

14  5 

H.  M.  S.: 
45  to  50... 

3 

42.8 

77.1 

17  5 

12  1 

50  to  55  ... 

3 

52.8 

83  6 

17  3 

12  7 

For  footnotes,  see  facing  page. 


EXPERIMENTS   WITH   HORIZONTAL   WALKING. 


145 


TABLE  35. — Metabolism  during  horizontal  walking  in  experiments  without  food,  grouped 
according  to  speed  of  walking.     (Average  values  per  minute.) — Continued. 


Heat-output  (computed). 

Subject  and 
speed  in 
meters. 

Pulse- 
rate. 

Carbon 
dioxide. 

Oxygen. 

Respira- 
tory 
quotient. 

*TI      4.      1 

Due  to 

Increase  over 
standing. 

lotal. 

stand- 
ing. 

Total. 

Per 

h.  kg.  m. 

A.  J.  O.: 

c.  c. 

c.  c. 

cols. 

cals. 

cats. 

gm.-cal. 

60  to  65 

608 

712 

0.85 

3.46 

1.31 

2.16 

0.460 

H.  R.  R.: 

60  to  65... 

*104 

670 

833 

.80 

4.00 

1.35 

2.64 

.605 

65  to  70..  . 

110 

754 

902 

.84 

4.47 

1.39 

3.08 

.625 

T.  H.  H.: 

60  to  65  ... 

«100 

559 

S651 

».86 

3.17 

1.11 

2.09 

.577 

65  to  70..  . 

*96 

579 

692 

.84 

3.36 

1.11 

2.23 

.579 

W.  K.: 

55  to  60..  . 

»75 

426 

519 

.82 

2.50 

1.10 

1.41 

.469 

60  to  65..  . 

•85 

447 

10558 

10.80 

2.68 

1.08 

1.60 

.494 

65  to  70... 

"84 

493 

7589 

T.84 

2.86 

1.13 

1.72 

.499 

E.  D.  B.: 

• 

35  to    40.. 

72 

393 

467 

.84 

2.26 

1.17 

1.10 

.499 

40  to    45.. 

»74 

409 

466 

.88 

2.28 

1.08 

1.20 

.467 

45  to    50.. 

868 

415 

467 

.89 

2.29 

1.08 

1.21 

.444 

50  to    55.. 

477 

449 

535 

.84 

2.59 

1.09 

1.49 

.469 

55  to    60.. 

«76 

18480 

563 

.85 

2.73 

1.13 

1.61 

.476 

60  to    65  .. 

1J95 

528 

633 

.83 

3.06 

1.15 

1.92 

.499 

65  to    70.. 

»78 

516 

586 

.88 

2.87 

1.16 

1.78 

.454 

70  to    75.. 

i»82 

543 

648 

.84 

3.14 

1.08 

2.07 

.482 

75  to    80.. 

*85 

580 

678 

.86 

3.31 

1.09 

2.11 

.478 

85  to    90.. 

»94 

705 

864 

.82 

4.17 

1.19 

2.97 

.552 

90  to  100.. 

98 

787 

901 

.87 

4.40 

1.17 

3.22 

.554 

J.  H.  G.: 

50  to  55..  . 

*98 

537 

697 

.77 

3.32 

1.34 

1.98 

.529 

55  to  60..  . 

!94 

558 

710 

.79 

3.40 

1.34 

2.06 

.535 

E.  L.  F.: 

45  to  50..  . 

100 

544 

674 

.81 

3.24 

1.24 

2.00 

.566 

50  to  55... 

89 

586 

717 

.82 

3.46 

1.31 

2.15 

.560 

H.  M.  S.: 

45  to  50... 

"93 

451 

601 

.75 

2.85 

1.13 

1.72 

.607 

50  to  55..  . 

"88 

500 

652 

.77 

3.11 

1.12 

1.98 

.568 

*5  periods. 

*10  periods. 

*6  periods. 

44  periods. 


*9  periods. 
•12  periods. 
T19  periods. 

88  periods. 


93  periods. 
1018  periods. 
11 14  periods. 
1228  periods. 


137  periods. 

Ml  period. 
U25  periods.. 
1831  periods. 


172  periods. 
18 17  periods. 


EFFECT  OP  SPEED  UPON  TOTAL  HEAT-OUTPUT. 


Considering  first  the  total  heat-output,  we  find  in  all  cases  an  increase 
with  each  increase  in  speed,  with  the  single  exception  of  E.  D.  B.  with 
a  speed  of  65  to  70  meters  per  minute.  This  exception  is  due  rather 
to  the  excessive  heat-output  for  the  preceding  group  of  values  at  60 
to  65  meters  per  minute.  Two-thirds  of  the  values  at  the  latter  speed 
were  obtained  during  the  early  part  of  this  subject's  experience  with 
the  treadmill,  namely,  in  October,  while  nearly  all  of  the  periods  hi  the 


146 


METABOLISM   DURING   WALKING. 


group  for  65  to  70  meters  were  taken  from  experiments  in  the  following 
months  of  November  and  December,  when  the  effect  of  training  had 
become  apparent.  This  single  exception  to  the  effect  of  increase  of 
speed  gives  evidence,  therefore,  of  the  effect  of  training  in  reducing  the 
energy  requirement. 

EFFECT  OF  SPEED  UPON  TOTAL  INCREASE  IN  HEAT-OUTPUT. 

The  energy-output  over  the  standing  requirement  likewise  increases 
with  the  increase  in  speed  in  much  the  same  manner  as  was  found  with 
the  total  heat-output.  This  may  be  seen  in  the  next  to  the  last  column 
of  table  35  and  graphically  in  figure  10.  The  high  values  for  E.  D.  B. 
at  60  to  65  meters  per  minute,  most  of  which  were  obtained  early  in  the 

TABLE  36. — Percentage  increase  in  heat-output  of  E.  D.  B.  due  to  walking 
on  a  level  at  various  speeds.     (Values  per  minute.) 


Range  of 
speed. 

Horizontal 
kilogram- 
meters. 

Increase  in 
heat  over 
standing 
requirement. 

meters. 

p.  ct. 

35  to    40 

2,212 

94 

40  to    45 

2,578 

111 

45  to    50 

2,722 

112 

60  to    55 

3,181 

137 

55  to    60 

3,371 

142 

60  to    65 

3,840 

167 

65  to    70 

3,929 

153 

70  to    75 

4,292 

192 

75  to    80 

4,584 

194 

85  to    90 

5,380 

250 

90  to  100 

5,849 

275 

Cerfs 

M 

?ftO 

/ 

s 

?40 

& 

? 

" 

??0 

3.90 

aoo 

2.60 
2.00 
160 
VOO 

Met 

r 

200 
180 
160 
140 
120 
100 

HRR. 

r 

_v 

^ 

[-0.8. 

* 

/ 

/ 

/ 

lit. 

^\ 

\y 

s 

•-• 

V 

_^»T.H 

>•»  — 

~s 

/ 

HMS 

,---" 
./ 

^ 

^ 

>/ 

-  t 

4" 

*""^ 

•-' 

^ 

ws   40     45     50     55     60     65     70      75     80     85     90     95     100 

FIG.  10. — Increments  in  total  heat-output  over  standing  re- 
quirement for  subjects  walking  on  a  level  at  different 
rates  in  meters  per  minute,  with  percentage  increase 
(broken  line)  for  E.  D.  B. 


EXPERIMENTS   WITH   HORIZONTAL   WALKING. 


147 


study  and  show  lack  of  training,  are  also  apparent  when  the  data  are 
presented  on  this  basis.  The  total  increase  in  the  heat-output,  calcu- 
lated on  the  percentage  basis,  is  given  for  E.  D.  B.  in  table  36.  These 
figures  show  that  for  slow  to  medium  speeds  of  walking  (35  to  80  me- 
ters per  minute,  that  is,  not  over  3  miles  an  hour),  the  per  minute  in- 
crease over  the  standing  requirement  ranged  from  94  to  194  per  cent, 
while  for  speeds  above  80  meters  per  minute  the  percentage  increase 
was  from  250  to  «275  per  cent.  These  percentage  values  for  the 
increase  in  the  total  heat  have  also  been  plotted  for  E.  D.  B.  in  the  form 
of  a  dotted-line  curve,  and  are  included  in  figure  10. 

These  increases  in  the  energy-output  are  given  for  all  of  the  subjects 
in  table  37  on  the  basis  of  per  meter  increase  in  speed,  and  show  that 
for  all  rates  of  walking  below  80  meters  per  minute  the  increase  in  the 
heat-output  varied  on  this  basis  from  0.024  calorie  for  E.  D.  B.  to 
0.071  calorie  for  H.  R.  R.  The  average  for  the  group  is  0.041  calorie. 
It  is  also  seen  from  the  detailed  values  for  E.  D.  B.  that  for  speeds  below 
57  meters  per  minute,  each  meter  increase  in  speed  required  an  increase 
in  heat  of  0.025  calorie,  and  from  57  to  78  meters  per  minute,  the  in- 
crease per  meter  was  0.024  calorie,  while  for  speeds  between  78  and 
96  meters  per  minute,  the  increase  per  meter  was  nearly  two  and  one- 
half  times  larger,  namely,  0.060  calorie. 

TABLE  37. — Heat-output  over  standing  requirements  per  1  meter  increase  in  speed  of  horizontal 

walking.     (Values  per  minute.) 


Subject. 

Range  of 
average 
speed.1 

Increase 
in  speed. 

Average 
increase  in 
total  heat- 
output  due 
to  increase 
in  speed. 

Average 
heat 
increase 
per  meter 
increase 
in  speed. 

H.  R.  R  

meters. 
60  .  9  to  67  .  1 

meters. 
6.2 

cals. 
0.44 

cals. 
0.071 

T.  H.  H  

63  .  2  to  67  .  1 

3.9 

.14 

.036 

W.  K  

68.3  to  66  6 

8.3 

.31 

.037 

E.  D.  B  

36  .  2  to  77  .  5 

41.3 

1.01 

.024 

J.  H.  G  

53  .  9  to  55  .  4 

1.5 

.08 

.053 

E.  L.  F  

49  .  1  to  52  .  6 

3.5 

.15 

.043 

H.  M.  S  

42  .  8  to  52  .  8 

10.0 

.26 

.026 

Average  .  . 
E.  D.  B  

52.1  to  62.  7 
36  .  2  to  66  .  5 

10.7 
20.3 

.34 
.51 

.041 
.025 

56.  5  to  77.  5 
77.  5  to  96.0 

21.0 
18.5 

.60 
1.11 

.024 
.060 

'See  third  column,  table  35. 
EFFECT  OF  SPEED  UPON  INCREASE  IN  HEAT  PER  HORIZONTAL  KILOGRAMMETER. 

A  summary  for  all  of  the  subjects  of  the  cost  per  horizontal  kilogram- 
meter  per  minute  as  affected  by  the  speed  is  given  in  table  38,  in  which 
are  included  the  average  results  for  the  two  subjects  of  Benedict  and 


148 


METABOLISM   DURING   WALKING. 


Murschhauser,  grouped  according  to  like  speeds.  The  table  shows  the 
wide  variations  which  may  be  found  with  different  subjects  and  also 
that  no  marked  effect  on  this  factor  is  evident  below  the  speed  of  80 
to  90  meters  per  minute  (approximately  3  miles  an  hour).  These 
average  values  are  likewise  given  in  the  form  of  curves  for  the  five 
principal  subjects.  (See  fig.  11.) 

TABLE  38. — Average  energy  cost  per  horizontal  kilogrammeler  of  walking  on  a  level  at  different  speeds. 

(Values  per  minute.) 


Subject. 

Energy  cost  (gm.-cal.)  per  h.  kg.  m.  at  various  speeds. 

35-40 
meters  . 

40-45 
meters  . 

45-50 
meters  . 

50-55 

meters  . 

55-60 
meters  . 

60-65 
meters  . 

65-70 
meters  . 

70-75 
meters  . 

75-80 
meters  . 

85-90 
meters  . 

90-100 
meters  . 

A.  J.  O. 

0.460 

H.  R.  R  

.605 
.577 
.494 
.499 

0.625 
.579 
.499 
.454 

T.  H.  H  

W.  K  

0.469 
.476 
.535 

E.  D.B  

0.499 

0.467 

0.444 

0.469 
.529 
.560 
.568 

0.482 

0.478 

0.552 

0.554 

J.  H.  G  

E.  L.  F  

.566 

H.  M.  S  

.607 

Average.  . 
Subject  I1..  . 

0.499 

.537 

.505 

.531 

.493 

.527 

.539 
.467 

.482 
.564 
.513 

.478 
.509 
.532 

.552 

.554 

Subject  II1.  . 

.521 

.498 

.  .527 

.524 

'Benedict  and  Murschhauser,  Carnegie  Inst.  Wash.  Pub.  No.  231,  1915. 


GRAM- 
CALORIE 


0.600 
.550 
£00 
.450 

.400 

METEI 

.-"- 

^•HR 

k 

*"- 

—  «r.M 

H. 

, 

waes^ 

E.0.8. 

9  _ 

^ 

/ 

y" 

*--v 

^ 

^~ 

•~^ 

V 

,--*•— 

-^ 

TO   40     45      50     55     60     65     70     75     80     86     90     95     1C 

FIG.  11. — Average  energy  cost  per  horizontal  kilogrammeter 
of  walking  on  a  level  at  various  distances  per  minute. 

From  table  38  and  figure  11  it  is  seen  that  an  increase  in  speed  is 
accompanied  by  an  increase  in  the  cost  per  horizontal  kilogrammeter 
with  H.  R.  R.  and  W.  K.,  but  practically  no  change  was  found  for 
T.  H.  H.  Table  38  also  shows  practically  no  change  for  J.  H.  G.  and 
E.  L.  F.,  but  with  H.  M.  S.  the  cost  per  horizontal  kilogrammeter  fell. 
The  curve  of  E.  D.  B.  as  a  whole  implies  that  there  is  practically  no 
increase  in  the  cost  per  horizontal  kilogrammeter  for  medium  speed, 
but  for  a  speed  above  80  to  85  meters  per  minute  the  cost  increases. 
The  group  for  the  slowest  speed,  that  for  35  to  40  meters  per  minute, 
shows  a  tendency  to  be  higher  than  the  succeeding  groups,  but  these 


EXPERIMENTS   WITH   HORIZONTAL   WALKING. 


149 


figures  are  the  average  of  two  days  in  April,  while  the  averages  for  the 
two  succeeding  groups  (40  to  45  meters  per  minute  and  45  to  50  meters 
per  minute)  were  from  experiments  made  in  November  and  December. 
The  lapse  of  time  between  these  groups  is  too  great,  therefore,  to  per- 
mit a  statement  that  the  cost  increases  as  the  speed  falls  below  a  cer- 
tain comfortable  rate  of  walking. 

The  effect  of  speed  upon  the  energy  cost  per  horizontal  kilogram- 
meter  can  best  be  shown  for  E.  D.  B.  by  a  consideration  of  the  data 
for  March  and  April,  in  which  there  is  a  wider  range  of  speed  and  the 
influence  of  training  is  largely  eliminated.  These  results  are  given  in 
table  39,  from  which  it  is  evident  that  for  moderate  speeds  ranging 
from  55  to  77  meters  per  minute,  the  cost  per  horizontal  kilogrammeter 
shows  no  tendency  to  change,  but  for  speeds  of  91  meters  per  minute 
the  cost  increased  nearly  20  per  cent.  The  latter  speed  was  a  forced 
one  and  required  considerable  exertion  on  the  part  of  E.  D.  B.  to 
maintain  it.  This  increase  in  the  energy  cost  is  in  full  agreement  with 
what  Durig  has  claimed,  namely,  that  the  cost  per  horizontal  kilo- 
grammeter is  practically  constant  for  speeds  below  80  to  85  meters  per 
minute,  above  which  speed  there  is  a  break  hi  the  curve  and  the  energy- 
output  increases  at  a  faster  ratio. 

TABLE  39. — Energy  cost  per  horizontal  kilogrammeter  with  E.  D.  B.  of  walking 
on  a  level  at  different  speeds  in  March  and  April  1916.     (Values  per  minute.) 


Date. 

Approximate 
distance 
walked. 

Average  heat 
perh.  kg.  m. 

1916. 
Apr.  3  and  4  

meters. 
37 

gm.-cal. 
0.499 

Mar.  29,  31,  and  Apr.  1  

55 

.466 

Mar.  20  and  30  

65 

.463 

Mar.  22,  Apr.  5,  and  10  

77 

.485 

Apr.  11,  12,  and  13  

91 

.553 

In  considering  the  extremely  slow  speed  of  37  meters  per  minute,  it  is 
seen  that  on  the  two  days  of  which  0.499  is  the  average  the  heat- 
output  was  0.475  and  0.522  gram-calorie  per  horizontal  kilogrammeter, 
respectively.  These  values  are,  unfortunately,  not  in  close  agreement. 
The  high  value  of  0.522  gram-calorie  for  April  4  might  be  taken  as  sup- 
porting the  statement  of  Frentzel  and  Reach,1  that  for  slow  restrained 
speeds  there  is  an  increase  in  the  heat  cost  per  horizontal  kilogram- 
meter.  This  claim  of  Frentzel  and  Reach  has  been  questioned  by 
Durig,2  who  believes  that  there  is  not  sufficient  evidence  in  Frentzel 
and  Reach's  figures  to  support  their  statement.  The  value  of  0.475 
gram-calorie  for  April  3  lies  close  to  the  values  found  for  all  the  other 

'Frentzel  and  Reach,  Archiv  f.  d.  ges.  Physiol.,  1901,  83,  p.  494. 

JDurig,  Denkschrift.  d.  math.-natur.  Klasse  d.  kaiserl.  Akad.  d.  Wissensch.,  1909,  86,  p.  271. 


150  METABOLISM   DURING   WALKING. 

days  for  speeds  up  to  78  meters  per  minute,  with  the  exception  of  that 
of  April  10,  while  the  value  of  0.522  gram-calorie  on  April  4  finds  no 
support  in  the  data  for  E.  D.  B.  outside  of  the  early  experiments  of 
October  and  that  of  January  31,  when  he  resumed  walking  after  an 
interval  of  three  weeks.  (See  p.  141.)  It  seems  probable  that  the 
value  of  0.475  gram-calorie  represents  more  nearly  the  true  condition 
than  does  the  value  0.522  gram-calorie,  in  which  case  it  would  appear 
to  be  in  agreement  with  Durig's  statement  that  there  is  no  increase  in 
the  energy  cost  per  horizontal  kilogrammeter  for  slow  walking.  Ob- 
viously a  study  of  the  energy  demands  for  extremely  slow  walking, 
i.  e.,  sauntering,  would  be  of  considerable  physiological  interest. 

Our  results  do  not  include  those  for  the  highest  speeds  of  walking, 
as  during  severe  grade  walking  slow  speeds  must  necessarily  be  em- 
ployed. In  any  consideration  of  the  literature  on  horizontal  walking 
special  attention  should  certainly  be  given  to  the  series  of  experiments 
of  Liljestrand  and  Stenstrom,1  in  which  the  Douglas  bag  was  used. 
With  both  subjects,  N.  S.  and  G.  L.,  the  energy  (expressed  as  oxygen 
consumption)  per  horizontal  kilogrammeter  shows  an  astonishingly 
uniform  agreement  with  all  of  the  best  earlier  work.  Since  in  some 
instances,  at  least,  the  actual  duration  of  these  experiments  was  but 
42  seconds,  this  speaks  for  not  only  the  great  applicability  of  the 
Douglas-bag  method,  but  likewise  for  the  extraordinary  technical  skill 
of  the  Swedish  investigators.  This  series  of  experiments  fully  sub- 
stantiates Douglas's  conclusions  as  to  the  applicability  of  his  bag 
method  to  studies  of  the  metabolism  during  exercise. 

EXPERIMENTS  WITH  SUBJECT  "MARKING  TIME." 

For  comparison  with  the  energy  requirements  of  horizontal  walking, 
it  seemed  of  interest  to  secure  a  few  measurements  when  the  subject 
simply  "marked  time,"  as  representing  a  degree  of  activity  interme- 
diate between  standing  and  walking.  Data  were  therefore  obtained 
with  W.  K.  which  are  given  in  table  40.  In  marking  time,  the  subject 
kept  his  legs  nearly  straight,  flexing  them  as  little  as  possible  at  the 
knees.  He  swung  the  leg  mostly  from  the  hip,  thus  lifting  the  body 
the  minimum  amount,  and  although  there  was  some  lifting  of  the 
limbs,  it  was  not  like  the  regulation  marking  time  of  the  army.  This 
movement  was  made  at  an  average  rate  of  101  so-called  "steps"  per 
minute.  Under  these  conditions  the  average  metabolism  per  minute 
of  W.  K.  was :  carbon  dioxide,  414  c.  c. ;  oxygen,  500  c.  c. ;  heat,  2.42  cals. 

By  consulting  table  35,  page  144,  it  is  seen  that  these  values  cor- 
respond very  nearly  to  his  requirement  for  horizontal  walking  at  a 
speed  of  55  to  60  meters  per  minute,  with  steps  taken  at  the  rate  of 
106.6  per  minute,  the  heat-output  differing  only  about  3  per  cent. 
It  would  seem  that  the  energy  necessary  for  horizontal  walking  is  almost 

Liljestrand  and  Stenstrom,  Skand.  Archiv  f.  Physiol.,  1920,  39,  pp.  178  and  179. 


EXPERIMENTS  WITH   HORIZONTAL   WALKING. 


151 


wholly  confined  to  that  for  the  muscular  effort  of  the  lower  limbs,  while 
the  oscillations  of  the  trunk  hi  keeping  the  body  balance  play  a  minor 
role.  This  finds  confirmation  in  some  experiments  reported  by  Waller1 
on  the  carbon-dioxide  production  during  horizontal  walking.  In  a  graph 
showing  the  carbon-dioxide  output  for  different  rates  of  walking,  he 
also  includes  that  for  marking  time  at  a  rate  of  120  steps  per  minute. 
He  does  not  discuss  this  portion  of  the  curve,  and  it  is  probable  that 
the  form  of  marking  time  was  different  from  that  which  we  used. 
However,  the  carbon-dioxide  output  indicated  by  his  curve  seems  to 

TABLE  40. — Metabolism  of  W.  K.  while  "marking  time"  in  experiments  without  food.     (Values  per  minute). 


Date. 

No.  of 
steps. 

Average 
respiration- 
rate. 

Average 
pulmonary 
ventilation 
(reduced). 

Average 
pulse- 
rate.1 

Carbon 
dioxide. 

Oxygen. 

Respira- 
tory 
quotient. 

Heat-out- 
put (com- 
puted) . 

1915. 
June  3  

92.2 

23.3 

liters. 
15.6 

74 

c.  c. 

420 

c.  c. 

485 

0.87 

cals. 
2.37 

97.2 
100.4 
100.4 

23.3 
23.1 
23.0 

15.9 
15.3 
15.4 

74 
76 
79 

429 
405 
416 

512 

487 
489 

.84 
.83 

.85 

2.48 
2.36 
2.38 

Average  .  . 

97.6 

23.2 

15.6 

76 

418 

493 

.85 

2.40 

June  4  

99.2 

22.9 

15.1 

74 

410 

485 

.85 

2.36 

22.0 

15.0 

74 

430 

507 

.85 

2.47 

105.0 
104.2 

22.2 
22.2 

14.8 
14.6 

77 
75 

419 
409 

500 
508 

.84 
.81 

2.43 
2.45 

Average  .  . 

102.8 

22.3 

14.9 

75 

417 

500 

.84 

2.43 

June  5  

102.0 

22.1 

14.8 

75 

412 

500 

.83 

2.42 

103.4 
104.4 
104.0 

21.7 
21.5 
21.8 

14.3 
14.1 
14.3 

77 

77 
78 

408 
401 
409 

515 

494 
515 

.80 
.81 

.80 

2.47 
2.38 
2.47 

Average.  . 

103.5 

21.8 

14.4 

77 

408 

506 

.81 

2.44 

•See  table  27  (page  111)  for  additional  records  for  pulse-rate  of  W.  K.  while  he  was  "marking  time. 

be  very  close  to  the  requirement  of  the  subject  when  walking  at  a 
speed  of  92  meters  per  minute,  or  130  steps  per  minute,  viz,  an  output 
of  972  c.  c.  of  carbon  dioxide  for  marking  time  and  960  c.  c.  for  walk- 
ing. That  is,  the  carbon-dioxide  requirement  for  marking  time  at  120 
steps  and  walking  at  130  steps  differed  only  by  1  per  cent. 

In  their  study  with  army  recruits,  Cathcart  and  Orr2  included  obser- 
vations of  the  respiratory  exchange  with  a  subject  "marking  time." 
In  10  experiments  after  meals  of  varying  composition  and  with  the 
man  carrying  loads  varying  from  5  to  20  kg.,  the  total  heat-output 
varied  from  209  to  271  calories  per  hour.  The  standing  value  was 
about  75  calories  per  hour.3  The  tempo  was  100  beats  per  minute. 


JWaller,  Journ.  Physiol.,  1919,  53,  Proc.  Physiol.  Soc.,  p.  xxiv. 
'Cathcart  and  Orr,  Energy  expenditure  of  the  infantry  recruit  in  training. 
Office,  London,  1919.     (See  table  47.) 

'See  subject  M,  tables  7  and  8  of  Cathcart  and  Orr,  loc.  cit. 


H.  M.  Stationery 


152 


METABOLISM   DURING  WALKING. 


They  note  that  the  energy  cost  of  "marking  time"  was  with  the  three 
greatest  loads  (16,  21,  and  26  kg.)  higher  than  that  for  slow  marching 
at  62.5  yards  (57.2  meters)  per  minute,  and  with  a  load  of  11  kg., 
"marking  time"  called  for  almost  identically  the  same  energy-output 
as  a  slow  march  of  57.14  meters  per  minute.  A  most  significant  dis- 
cussion of  "marking  time"  is  presented  by  Cathcart  and  Orr.1 

The  energy  requirement  for  "marking  time"  is  considerably  larger 
than  one  would  anticipate  and  shows  that  unnecessary  and  extraneous 
movements  might  easily  lead  to  considerable  differences  in  the  metab- 
olism measurements  with  muscular  work  of  a  moderate  degree  of 
intensity.  Benedict  and  Murschhauser2  have  called  attention  to  this 
in  some  measurements  in  which  their  subject  stood  and  swung  his 
arms  and  hands  as  in  fast  walking,  with  the  result  that  there  was  an 
increase  of  126  per  cent  over  his  quiet  standing  metabolism. 

STEPS  AND  STEP-LIFT  DURING  HORIZONTAL  WALKING. 

As  was  stated  in  an  earlier  section  (p.  33),  a  record  was  kept  of  the 
number  of  steps  the  subject  took  in  walking,  and  measurements  were 
frequently  made  of  the  height  to  which  the  subject  lifted  his  body  as  a 
result  of  the  heel-and-toe  action  in  walking.  These  records  are  given 
in  detail  in  tables  29  to  33.  The  daily  averages  are  summarized 
according  to  the  speed  of  walking  in  table  41,  in  which  the  average 
length  of  step  is  also  included.  It  is  believed  that  the  number  of  steps 
taken  is  accurately  known,  and  therefore  the  average  length  of  step  is 
without  appreciable  error.  This  can  not  be  so  fully  claimed,  however, 
for  the  height  of  the  step-lift,  as  will  be  shown  later.  (See  p.  155.) 

TABLE  41. — Number  of  steps  and  height  of  step-lift  in  walking  on  a  level.     (Values  per  minute.) 


Subject  and 
date. 

Distance 
walked. 

No.  of 
steps. 

Step-lift. 

Step-lift 
per  step. 

Length  of 
step. 

A.  J.  O.: 
Mar.    2  

meters. 
62.7 

96.8 

meters. 
2.09 

cm. 
2.16 

cm. 
64.8 

Feb.  24  

63.5 

96.9 

1.87 

1.93 

65.5 

H.  R.  R.: 

Apr.   17  

60.0 

98.1 

1.05 

1.07 

61.2 

3  

60.5 

95.3 

1.11 

1.16 

63.5 

24  

60.7 

98.3 

1.20 

1.22 

61.7 

10  

61.1 

99.0 

1.02 

1.03 

61.7 

Mar.  20  

66.1 

103.8 

.92 

.89 

63.6 

27  

66.8 

102.6 

1.35 

1.32 

65.1 

T.  H.  H.: 

Apr.     5  

62.8 

100.2 

1.79 

1.79 

62.7 

Feb.  25  

63.6 

99.0 

1.61 

1.63 

64.2 

Mar.  30  

65.4 

101.3 

2.03 

2.00 

64.6 

19  

66.8 

106.4 

1.73 

1.63 

62.8 

26  

67.2 

101.3 

2.13 

2  10 

66.3 

22  

67.5 

105.8 

1.29 

1.22 

63.8 

24  

67.8 

104.2 

1.83 

1.76 

65.1 

'Cathcart  and  Orr,  loc.  tit.,  p.  54. 

*Benedict  and  Murschhauser,  Carnegie  Inst.  Wash.  Pub.  No.  231,  1915,  pp.  71  and  97. 


EXPERIMENTS   WITH   HORIZONTAL   WALKING.  153 

TABLE  41. — Number  of  steps  and  height  of  step-lift  in  walking  on  a  level.     (Values  per 

minute.) — Continued . 


Subject  and 
date. 

Distance 
walked. 

No.  of 
steps. 

Step-lift. 

Step-lift 
per  step. 

Length  of 
step. 

W.  K.: 
June  23  

meters. 
57.1 

106.5 

meters. 
1.28 

cm. 

1.20 

cm. 
53.6 

Mar.  18  

60.1 

104.6 

1.01 

.97 

57  5 

16  

60.8 

108.3 

.81 

.75 

56.1 

13  

62.1 

110.6 

1.07 

.97 

56.1 

9  

62.3 

110.2 

.97 

.88 

56.5 

29  

62.3 

109.3 

1.17 

1.07 

57.0 

12  

62.5 

112.9 

1.21 

1.07 

55.4 

4  

64.3 

114.5 

1.27 

1.11 

56.2 

Feb.  26  

64.4 

114.7 

1.40 

1.22 

56.1 

Mar.  31  

65.1 

108.8 

1.18 

1.08 

59.8 

23  

65.7 

112.1 

1.28 

1.14 

58.6 

5  

65.8 

115.0 

1.55 

1.35 

57.2 

8  

66.5 

116.1 

1.49 

1.28 

57.3 

25  

67.3 

112.7 

2.03 

1.80 

59.7 

17  

67.5 

116.2 

1.46 

1.26 

58.1 

E.  D.  B. 

Nov.    2  

43.2 

79.9 

.70 

.88 

54.1 

Oct.   30  

43.9 

80.3 

.66 

.82 

54.7 

Nov.    1  

44.3 

79.7 

.72 

.90 

55.6 

3  

44.5 

85.3 

.76 

.89 

52.2 

Dec.     6  

45.0 

78.5 

.68 

.87 

57.3 

Nov.  17  

45.7 

79.0 

.78 

.99 

57.8 

Dec.     7  

45.8 

77.1 

.67 

.87 

59.4 

Nov.    6  

45.9 

80.8 

.75 

.93 

56.8 

5  

46.2 

81.9 

.81 

.99 

56.4 

Dec.     4  

46.7 

79.0 

.93 

1.18 

59.1 

Nov.  22  

47.4 

80.7 

.79 

.98 

58.7 

10  

47.8 

84.7 

1.00 

1.18 

56.4 

4  

53.5 

86.5 

1.17 

1.35 

61.8 

Oct.    15  

54.4 

88.8 

1.15 

1.30 

61.3 

14  

54.5 

88.1    • 

1.34 

1.51 

61.9 

Nov.    9  

54.7 

88.0 

1.19 

1.35 

62.2 

23  

54.8 

87.7 

1.26 

1.44 

62.5 

Oct.    11  

55.0 

92.9 

1.40 

1.51 

59.2 

Nov.  18  

55.0 

88.3 

1.21 

1.37 

62.3 

Oct.    13  

55.8 

87.0 

1.34 

1.54 

64.1 

Nov.    8  

56.1 

89.0 

1.26 

1.42 

63.0 

Oct.     9  

57.1 

93.0 

1.30 

1.40 

61.4 

Nov.  24  

57.5 

90.0 

1.37 

1.52 

63.9 

Jan.   31  

63.2 

96.0 

2.50 

2.60 

65.8 

Feb.     1  

63.6 

94.2 

2.23 

2.37 

67.5 

Oct.   21  

63.8 

97.3 

1.87 

1.92 

65.6 

18  

64.3 

96.4 

1.78 

1.85 

66.7 

19  

64.3 

96.5 

1.83 

1.88 

66.6 

20  

64.6 

97.6 

1.87 

1.92 

66.2 

16  

65.0 

97.6 

1.73 

1.77 

66.6 

Nov.  26  

65.9 

98.3 

1.66 

1.69 

67.0 

Dec.  13  

66.7 

97.6 

2.07 

2.12 

68.3 

Nov.  12  

67.1 

99.1 

1.92 

1.94 

67.7 

11  

67.9 

99.0 

2.46 

2.48 

68.6 

Dec.     3  

71.3 

101.9 

2.56 

2.52 

70.0 

2  

71.6 

101.8 

2.49 

2.45 

70.3 

Oct.   23  

72.2 

101.1 

2.13 

2.12 

71.4 

22  

72.3 

100.5 

2.06 

2.05 

71.9 

26  

72.9 

102.4 

2.47 

2.41 

71.2 

25  

73.2 

101.4 

2.50 

2.47 

72.2 

Dec.     1  

76.2 

105.3 

2.72 

2.58 

72.4 

154 


METABOLISM   DURING  WALKING. 


TABLE  41. — Number  of  steps  and  height  of  step-lift  in  walking  on  a  level. 

minute.) — Continued. 


(Values  per 


Subject  and 
date. 

Distance 
walked. 

No.  of 
steps. 

Step-lift. 

Step-lift 
per  step. 

Length  of 
step. 

E.  D.  B.  —  Con. 
Nov.  13  

meters. 
76.7 

103.9 

meters. 
2.75 

cm. 
2.65 

cm. 
73.8 

16  

76.9 

103.7 

2.90 

2.80 

74.2 

15  

77.0 

104.0 

2.83 

2.72 

74.0 

Oct.    27  

77.7 

104.5 

2.91 

2.78 

74.4 

28  

77.8 

106.5 

2.78 

2.61 

73.1 

Nov.  19  

77.9 

104.1 

2.43 

2.33 

74.8 

Oct.   29  

78.0 

104.8 

2.95 

2.81 

74.4 

J.  H.  G.: 
Jan.    19  

54.7 

101.0 

1.65 

1.65 

54.2 

18  

55.0 

88.1 

1.31 

1.49 

62.4 

20  

55.0 

97.1 

1.71 

1.75 

56.6 

E.  L.  F.: 
Jan.    24  

49.1 

95.7 

1.61 

1.69 

51.3 

21  

52.4 

90.3 

1.78 

1.97 

58.0 

22  

52.8 

94.9 

1.79 

1.79 

55.6 

H.  M.  S.: 
Jan.   25  

42.8 

77.1 

1.71 

2.22 

55.5 

26  

52.8 

83.6 

2.36 

2.82 

63.2 

NUMBER  OF  STEPS  IN  HORIZONTAL  WALKING. 

In  adapting  himself  to  a  definite  speed,  the  subject  may  either  change 
his  length  of  stride  or  the  number  of  his  steps,  and,  in  fact,  he  does  both. 
It  is  to  be  expected  that  for  slower  speeds  there  will  be  fewer  steps,  also 
that  the  strides  will  be  shorter;  but  even  for  the  same  speed  it  is  seen 
that  on  different  days  there  is  a  change  in  both  the  number  and  length 
of  steps.  This  difference  amounts  in  some  cases  to  as  much  as  6  or 
7  steps  per  minute.  W.  K.,  who  was  the  shortest  subject,  shows  the 
most  steps  per  minute  for  a  given  speed,  the  number  of  steps  at  a  speed 
of  67.5  meters  being  10  more  per  minute  than  the  number  for  T.  H.  H. 
at  the  same  speed  and  14  more  than  for  H.  R  .R.,  the  tallest  subject, 
at  approximately  the  same  rate  of  walking.  On  the  other  hand, 
E.  D.  B.,  who  was  shorter  than  H.  R.  R.,  took  even  fewer  steps  per 
minute  than  the  latter,  as  may  be  seen  by  comparing  the  data  for 
November  26  and  December  13  for  E.  D.  B.  with  those  for  March  20 
and  27  for  H.  R.  R. 

These  variations  make  it  impossible  to  draw  any  definite  conclusions 
even  for  the  same  subject.  One  can  only  say  that  a  man,  walking  at 
normal  and  constant  speed,  may  unconsciously  alter  his  gait  four  or 
more  steps  per  minute,  and  although  the  difference  between  individuals 
depends  in  a  large  measure  upon  the  length  of  leg  of  the  subjects,  it  is 
possible  for  a  shorter  man  to  take  natural  strides  which  are  longer 
than  those  taken  by  a  taller  individual.  The  number  of  steps  repre- 
sents to  a  certain  degree  the  amount  of  effort  exerted  hi  walking,  but 
evidently,  at  least  with  these  subjects  and  the  rates  of  speed  here  used, 
the  number  does  not  appear  to  be  proportional  to  the  energy  expended. 


EXPERIMENTS   WITH   HORIZONTAL   WALKING.*  155 

The  average  number  of  steps  taken  by  E.  D.  B.  at  different  speeds 
is  shown  in  table  42.  (See  p.  156.)  The  increase  in  the  number  of 
steps  with  greater  speed  is  not  regular,  but  shows  a  diminishing  rate 
as  the  speed  increases.  Thus,  the  number  of  steps  was  8.4  greater  for 
55  meters  per  minute  than  for  45  meters  per  minute,  or  an  increase  of 
0.84  step  for  each  meter  per  minute  increase  in  speed,  and  0.82  step 
when  the  speed  became  65  meters  per  minute.  The  increase  to  72  and 
77  meters  per  minute  was  accompanied  by  an  increase  of  practically 
0.62  per  meter  increase  in  speed  hi  each  case.  With  E.  D.  3.,  there- 
fore, the  increase  in  the  speed  of  walking  appears  to  have  been  more 
nearly  taken  care  of  at  the  lower  speeds  by  an  increase  in  the  number 
of  steps,  but  with  the  higher  speeds  this  became  a  lessening  factor. 

STEP-LIFT  DURING  HORIZONTAL  WALKING. 

In  considering  the  data  recorded  in  tables  29  to- 33  for  the  elevation 
of  the  body,  or  what  we  have  termed  the  step-lift,  it  is  recognized  that 
there  are  considerable  variations  in  this  factor  for  the  same  subject  at 
the  same  speed  on  different  days,  and  also  that  substantial  differences 
appear  at  times  for  the  same  subject  in  the  periods  for  the  same  day. 
This  would  naturally  lead  to  a  questioning  of  the  technique  by  which 
the  measurements  were  made. 

POSSIBLE  CAUSES  FOR  VARIATION  IN  STEP-LIFT. 

The  most  apparent  fault  in  the  technique  whiqh  would  lead  to  these 
differences  in  the  records  would  be  a  failure  to  have  the  fork  of  the 
recording  device  (see  fig.  l,p.  19)  held  firmly  against  the  shoulder  of 
the  subject,  thereby  not  giving  the  full  effect  of  the  step  to  the  counter. 
It  is,  of  course,  possible  that  an  error  may  have  occurred  in  this  way  in 
a  few  instances,  but  as  it  was  recognized  that  such  difficulty  might  occur 
we  were  especially  careful  to  be  on  the  watch  for  it.  Another  source  of 
error  would  be  in  the  slipping  of  the  cord  on  the  periphery  of  the  wheel 
which  operated  the  counter,  This  would  naturally  produce  too  low 
a  registration.  This,  we  know,  did  occur  in  a  few  instances,  and  in 
such  cases  we  have  made  use  of  the  kymograph  record  in  estimating 
the  lift.  After  such  conditions  were  discovered,  it  was  the  practice  to 
rub  a  little  powdered  rosin  on  the  cord  at  the  beginning  of  each  period. 
Even  with  this  precaution  and  when  no  slipping  was  apparent,  dif- 
ferences were  still  found  in  the  elevation.  It  seems  probable,  there- 
fore, that  this  difference  was  due  to  the  gait  of  the  subject,  produced 
either  by  more  shoulder-motion  or  by  a  lateral  swaying  of  the  body 
or  by  a  difference  in  the  absolute  lift.  It  should  be  recalled  that  if 
a  subject,  while  taking  100  steps  a  minute,  lifted  his  body  1  cm.  a  step, 
it  would  require  a  displacement  of  only  2  mm.  from  any  cause  to  produce 
a  variation  of  20  per  cent  in  the  final  reading.  That  the  subject 
changed  his  gait  by  changing  the  number  and  length  of  his  steps  has 
been  shown  in  the  preceding  section,  but  how  much  this  change  in  the 


156 


METABOLISM   DURING  WALKING. 


measured  step-lift  is  due  to  one  or  the  other  of  these  causes  we  do  not 
know.  Though  these  differences  make  the  measurements  of  less  con- 
sequence, nevertheless  we  believe  that  the  values  obtained  have 
enough  interest  to  present. 


TOTAL  STEP-LIFT  PER  MINUTE. 


A  survey  of  the  figures  in  tables  29  to  33  and  41  shows  that  for  the 
ranges  of  speed  employed  the  step-lift  per  minute  varied  approxi- 
mately from  1  to  3  meters,  and  that  a  tall  man  like  H.  R.  R.  had  a  total 
lift  per  minute  of  about  the  same  degree  as  that  of  a  short  man  like 
W.  K.,  who  had  to  take  more  steps  to  cover  the  same  distance  The 
relation  of  speed  to  the  step-lift  is  best  shown  by  the  results  obtained 
for  E.  D.  B.,  with  whom  a  larger  amount  of  data  was  obtained.  (See 
table  41.) 

It  may  be  of  interest  to  note  the  average  values  on  the  basis  of  speed. 
This  comparison  is  made  for  E.  D.  B.  in  table  42,  in  which  we  find 
that  the  average  per  minute  step-lift  at  45  meters  per  minute  was  0.77 
meter;  for  55  meters,  1.27  meters;  for  65  meters,  1.99  meters;  for  72 
meters,  2.37  meters;  and  for  77  meters,  2.78  meters. 

TABLE  42. — Relationship  between  step-lift  and  speed  of  walking  in  horizontal-walking  experi- 
ments without  food  with  E.  D.  B.     (Values  per  minute.) 


Increment 

Total 

Average 
speed,  in 
meters. 

Range  in 
total 
step-lift. 

Average 
total 
step-lift. 

in  total 
step-lift 
per  meter 
increase 

step-lift 
per  meter 
of 
distance 

Average 
No.  of 
steps. 

Average 
step-lift 
per  step. 

in  speed. 

walked. 

meters. 

meters. 

cm. 

cm. 

- 

cm. 

45 

0  .  66  to  1  .  00 

0.77 

1.71 

80.6 

0.96 

55 

1.15  to  1.40 

1.27 

5.0 

2.31 

89.0 

1.43 

65 

1.66to2.50 

1.99 

7.2 

3.06 

97.2 

2.05 

72 

2.  06  to  2.  56 

2.37 

5.4 

3.29 

101.5 

2.34 

77 

2.  43  to  2.  95 

2.78 

8.2 

3.61 

104.6 

2.66 

But  of  special  significance  is  the  increment  in  the  total  step-lift  per 
minute  due  to  each  meter  change  in  speed.  In  passing  from  a  speed 
of  45  to  55  meters  per  minute,  the  total  step-lift  per  minute  increased 
on  the  average  for  each  meter  increase  in  speed  5  cm. ;  from  55  to  65 
meters,  7.2  cm. ;  from  65  to  72  meters  (a  change  in  speed  of  but  7  me- 
ters), the  increment  was  5.4  cm.;  and  from  72  to  77  meters  (a  change 
in  speed  of  only  5  meters),  the  increase  in  the  total  step-lift  was  8.2  cm. 
per  meter  increase  in  speed.  These  increments  per  meter  increase  in 
speed,  which  are  given  in  table  42,  show  rather  extraordinary  irregu- 
larity hi  the  values. 

Finally,  we  should  observe  the  step-lift  per  meter  of  distance  trav- 
eled. It  is  seen  that  at  45  meters  per  minute  the  step-lift  was  1.71 


EXPERIMENTS   WITH   HORIZONTAL   WALKING.  157 

cm.  per  meter;  at  55  meters,  2.31  cm. ;  at  65  meters,  3.06  cm. ;  at  72  me- 
ters, 3.29  cm.;  and  at  77  meters,  3.61  cm.  These  values  show,  there- 
fore, that  the  step-lift  per  meter  of  distance  traveled  was  somewhat  less 
at  the  lower  speeds.  This  fact  is  contrary  to  the  evidence  in  several 
of  our  experiments,  from  which  it  appeared  that  the  energy  expendi- 
ture per  horizontal  kilogrammeter  tended  to  be  somewhat  greater  at 
the  extremely  slow  speeds.  This  again  emphasizes  the  importance  of 
studying  more  in  detail  the  physiology  of  walking  at  slow  or  "saunter- 
ing" speeds. 

STEP-LIFT   PER   STEP. 

It  is  possible  that  the  change  in  number  and  length  of  steps  to  obtain 
a  desired  speed  might  not  affect  the  lift  per  step  and  that  it  would  re- 
main relatively  uniform.  An  inspection  of  the  figures  for  the  lift  per 
step  in  table  41  shows  that  the  same  variations  are  present  here  that 
were  found  in  the  number  of  steps  and  in  the  total  step-lift  per  minute. 
Not  only  are  there  variations  between  individuals  for  the  same  speed, 
but  for  the  same  individual  at  the  same  speeds  on  different  days  varia- 
tions appear  which,  though  not  large  in  themselves,  amount  to  as  much 
as  20  per  cent  of  the  total  step-lift  per  minute.  Thus  W.  K.,  walking 
at  a  speed  of  62.3  meters  per  minute,  had  a  step-lift  per  step  on  March  9 
of  0.88  cm.  and  on  March  29  of  1.07  cm.,  with  a  difference  of  0.19  cm., 
or  21  per  cent.  With  the  faster  speeds,  the  step-lift  is  greater  when  the 
extreme  speeds  are  compared,  but  with  the  slower  speeds  there  are 
numerous  instances  when  there  was  a  greater  step-lift  per  step  than 
with  speeds  a  few  meters  faster.  In  the  long  series  with  E.  D.  B.  it 
appears  that  all  speeds  over  70  meters  per  minute  were  accompanied  by 
a  step-lift  per  step  of  2  cm.  or  more,  and  with  two  exceptions,  speeds 
under  50  meters  per  minute  had  a  step-lift  per  step  of  less  than  1  cm. 
The  high  values  for  January  31  and  February  1,  1916,  fall  quite  out 
of  the  regularity  of  the  series.  The  conditions  involving  the  indi- 
vidual gaits  are  apparently  too  complex  for  a  simple  analysis,  and  only 
general  impressions  can  be  obtained  from  the  measurements. 

Table  42  also  shows  the  average  step-lift  per  step  for  E.  D.  B.  with 
change  in  the  average  speeds.  Here,  as  in  the  case  of  the  total  step- 
lift  per  meter  distance,  there  is  an  absence  of  uniformity  in  the  amount 
of  increase  in  the  step-lift,  though  the  increase  is  progressive  in  each 
instance. 

ENERGY  INCREMENT  DUE  TO  WORK  OP  STEP-LIFT. 

By  multiplying  the  step-lift  as  given  in  meters  by  the  body-weight 
of  the  subject,  it  is  possible  to  obtain  the  kilogrammeters  of  work  done 
due  to  this  elevation  of  the  body.1  From  this  the  heat-output  per 
kilogrammeter  of  step-lift  has  been  computed.  (See  column  /  of 

'It  is  most  important  to  note  that  the  effort  of  sustaining  and  lowering  the  body  is  entirely  dis- 
regarded in  this  calculation. 


158  METABOLISM   DURING   WALKING. 

tables  29  to  33.)  By  using  the  factor  426.6  for  the  mechanical  equiva- 
lent of  heat,1  we  may  likewise  compute  the  probable  proportion  of  the 
increment  in  the  heat-output  which  was  due  to  the  work  of  the  step- 
lift.  These  percentages  are  given  for  each  experiment  in  the  last 
column  of  tables  29  to  33,  in  which  2.34  gram-calories  is  taken  as  the 
heat  equivalent  of  1  kg.  m. 

Thus,  by  reference  to  table  29,  we  find  that  A.  J.  O.,  with  a  body- 
weight  of  75  kg.  and  walking  at  a  speed  of  63.1  meters  per  minute, 
accomplished  on  February  24  in  the  first  period  4,733  h.  kg.  m.  per 
minute,  and  by  his  steps  lifted  his  body  to  an  elevation  of  1.72  meters 
in  1  minute,  thus  performing  129  kg.  m.  of  work.  His  standing  basal 
metabolism  for  this  day  was  1.30  calories  per  minute.  His  walking 
metabolism  for  this  period  was  3.67  calories.  The  increase  due  to  the 
walking  was  therefore  2.37  calories,  which  is  equivalent  to  0.501  gram- 
calorie  per  horizontal  kilogrammeter,  and  18.4  gram-calories  per  kilo- 
grammeter  of  work  for  the  step-lift. 

The  values  for  the  energy  cost  of  this  work  of  lifting  the  body  (see 
column  j,  tables  29  to  33)  show  expenditures  from  as  high  as  47  gram- 
calories  per  kilogrammeter  for  H.  R.  R.  to  as  low  as  12  gram-calories  for 
E.  D.  B.  The  average  cost  per  kilogrammeter  of  step-lift  for  A.  J.  O. 
is  15.3  gram-calories,  with  a  percentage  of  increment  due  to  the 
elevation  of  the  body  of  14  to  17  per  cent.  The  percentage  of  incre- 
ment for  H.  R.  R.  is  as  low  as  5  per  cent  on  his  first  day  of  walking  and 
does  not  exceed  8  per  cent  at  other  tunes.  With  T.  H.  IJ.  the  average 
cost  per  kilogrammeter  due  to  step-lift  was  22.1  gram-calories,  and  the 
average  percentage  of  increment  11  per  cent. 

The  values  for  W.  K.  show  considerable  variation,  the  elevation  of 
the  body  ranging  in  the  periods  between  0.7  and  2.07  meters  per  min- 
ute, with  the  amount  of  work  done  varying  between  36.8  and  104.5  kilo- 
grammeters.  The  least  amount  of  work  done  was  on  March  16,  and 
these  values  are  so  much  less  than  the  other  values  for  this  subject  that 
they  may  fairly  be  questioned.  The  original  records  show  nothing, 
however,  to  indicate  any  defect  in  the  technique  to  account  for  this 
variance.  The  average  heat-output  per  kilogrammeter  due  to  step- 
lift  was  25.5  gram-calories,  with  considerable  variation  from  day  to 
day.  The  daily  average  for  the  percentage  of  increment  due  to  step- 
lift  ranged  from  6  per  cent  on  March  16  to  14  per  cent  on  March  25. 
The  average  for  the  first  6  days  in  March  was  9  per  cent  and  of  the 
last  6  days  10  per  cent,  but  this  difference  is  not  sufficient  to  imply  any 
improvement  in  this  respect,  as  these  figures  can  at  best  be  considered 
as  only  approximate. 

'Armsby,  Principles  of  animal  nutrition,  New  York,  2d  ed.,  1906,  p.  233.  A  so-called  "best" 
value  of  426.7  is  reported  in  the  Smithsonian  Physical  Tables,  Washington,  1920,  7th  rev.  ed., 
table  212,  p.  197.  Our  computations  were  made  previous  to  the  publication  of  this  edition  by 
means  of  the  slightly  lower  figure. 


EXPERIMENTS   WITH   HORIZONTAL   WALKING. 


159 


For  the  subjects  as  a  group,  with  walking  at  average  speeds,  the 
percentage  increments  due  to  step-lift  range  usually  from  8  to  14  per 
cent,  while  with  higher  speeds  a  value  for  E.  D.  B.  was  found  of  18  or 
19  per  cent.  Benedict  and  Murschhauser1  report  a  step-lift  of  3.78 
meters  for  their  Subject  I  while  he  was  walking  at  a  speed  of  75.9  me- 
ters per  minute.  Since  his  body- weight  was  73. 1  kg.,  this  corresponded 
to  a  work  equivalent  of  276.32  kilogrammeters,  or  an  energy  require- 
ment of  0.65  calorie  per  minute,  which  was  approximately  23  per  cent 
of  the  total  energy  increment  due  to  walking.  This  value  is  much 

TABLE  43. — Effect  of  training  on  step-lift  and  on  proportion  of  heat-output  expended  in  such 
movement.  Subject,  E.  D.  B.,  horizontal-walking  experiments  without  food.  October  SO, 
1916,  to  February  1,  1916.  (Values  per  minute.) 


Date  and 
speed. 

Average 
step-lift. 

Proportion 
of  increase 
in  heat  due 
to  step-lift. 

Date  and 
speed. 

Average 
step-lift. 

Proportion 
of  increase 
in  heat  due 
to  step-lift. 

43  to  48  meters: 

meters. 

p.  ct. 

60  to  68  meters: 

meters. 

p.  ct. 

Oct.   30. 

0.66 

7 

Oct.    16.      . 

1.73 

12 

Nov.    1. 

.72 

8 

18.      . 

1.78 

14 

2. 

.70 

8 

19.      . 

1.83 

13 

3. 

.76 

9 

20.      . 

1.87 

13 

5. 

.81 

9 

21.      . 

1.87 

13 

6. 

.75 

9 

Nov.  11.      . 

2.46 

19 

10. 

1.00 

11 

12.      . 

1.92 

15 

17. 

.78 

9 

26.      . 

1.66 

14 

22. 

.79 

9 

Dec.  13.      . 

2.07 

17 

Dec.     4. 

.93 

11 

Jan.   31.      . 

2.50 

17 

6. 

.68 

9 

Feb.     1  .      . 

2.23 

18 

7. 

.67 

8 

71  to  73  meters  : 

52  to  58  meters: 

Oct.   22.      . 

2.06 

14 

Oct.     9  . 

1.30 

9 

23.      . 

2.13 

14 

11. 

1.40 

11 

25.      . 

2.50 

16 

13. 

1.34 

10 

26.      . 

2.47 

16 

14. 

1.34 

11 

Dec.     2  .      . 

2.49 

19 

15. 

1.15 

9 

3.      . 

2.56 

19 

Nov.    4  . 

1.17 

12 

76  to  78  meters: 

8. 

1.26 

12 

Oct.    27.      . 

2.91 

18 

9. 

1.19 

12 

28.      . 

2.78 

17 

18. 

1.21 

11 

29.      . 

2.95 

18 

23. 

1.26 

13 

Nov.  13.      . 

2.75 

19 

24. 

1.37 

14 

15.      . 

2.83 

19 

16.      . 

2.90 

19 

19.      . 

2.43 

15 

Dec.     1  .      . 

2.72 

18 

higher  than  that  found  for  any  of  our  subjects,  the  nearest  approach 
to  it  for  similar  speed  being  that  for  E.  D.  B.,  who,  on  December  1, 
walked  at  a  speed  of  76.2  meters  per  minute,  with  a  step-lift  of  2.72 
meters  per  minute,  using  18  per  cent  of  the  heat  expended  for  horizontal 
progression  in  the  step-lift. 

The  effect  of  training  on  the  step-lift  and  on  the  heat-output  due  to 
this  factor  may  be  studied  by  reference  to  table  43,  in  which  have  been 

Benedict  and  Murschhauser,  Carnegie  Inst.  Wash.  Pub.  No.  231,  1916,  p.  80. 


160  METABOLISM   DURING   WALKING. 

grouped  the  average  step-lift  per  day  for  various  speed  groups  and  also 
the  percentage  of  the  heat-output  expended  due  to  this  step-lift. 
An  inspection  of  these  figures  shows  no  uniform  change  in  the  step- 
lift  for  a  definite  speed  as  the  experiments  continued,  except  possibly 
with  the  60  to  68  meter  group.  In  several  groups,  the  percentage  of  the 
increment  in  the  heat-output  due  to  the  step-lift  increased  somewhat  as 
time  progressed.  As  has  already  been  seen  in  other  groupings  of  the 
results,  these  figures  show  that  as  the  speed  increased,  the  step-lift 
also  increased,  likewise  the  percentage  of  the  increment  in  heat  due  to 
the  step-lift. 

The  above  consideration  of  the  step-lift  suggests  several  important 
lines  of  study,  for  if  the  step-lift  involves  a  minimum  of  from  10  to  20 
per  cent  of  the  energy  required  above  basal  for  the  work  of  forward  pro- 
gression, it  can  readily  be  seen  that  a  type  of  gait  which  would  mini- 
mize the  step-lift  would  tend  to  decrease  this  factor.  Doubtless  the 
time  relations  of  elevation,  sustained  suspension,  and  lowering  of  the 
body  in  typical  and  atypical  gaits  would  throw  much  light  on  this 
important  problem  of  efficient  and  economical  horizontal  walking. 
That  such  a  study  should  likewise  consider  the  gait  in  grade  walking 
is  obvious.  It  is  the  current  practice  of  experienced  mountaineers  to 
alter  their  gait  frequently. 

PHYSIOLOGICAL  EFFECTS  OF  HORIZONTAL  WALKING. 

As  was  done  in  the  standing  experiments,  records  were  obtained  in 
these  walking  experiments  of  the  respiration-rate,  pulmonary  ventila- 
tion, pulse-rate,  and,  in  some  of  the  experiments,  especially  with 
E.  D.  B.,  the  body-temperature  and  blood-pressure.  The  detailed 
records  are  given  in  the  statistical  tables  8  to  12,- and  the  daily  averages 
grouped  according  to  speed  in  table  35.  A  summary  is  also  given  in 
table  44,  in  which  not  only  the  averages  for  the  speed  groups  are  given, 
but  also  the  number  of  experimental  periods  on  which  the  speed-group 
data  are  based,  and  the  increments  due  to  the  activity  of  walking. 
These  increments  have  been  calculated  by  using  as  a  basal  value  for 
each  subject  the  average  of  the  values  obtained  in  his  standing  experi- 
ments. (See  tables  3  to  7.) 

RESPIRATION-RATE  DXTRING  HORIZONTAL  WALKING. 

From  tables  8  to  12,  and  35,  and  the  summary  in  table  44,  it  is  seen 
that  individual  subjects  show  wide  individual  differences.  For  the 
same  subject  the  increase  in  the  respiration-rate  for  the  moderate 
speeds  of  walking  was  gradual  and  no  larger  than  the  variations  in  the 
results  for  an  individual  with  a  definite  speed.  This  applies  with 
E.  D.  B.  up  to  an  average  speed  of  77.5  meters  per  minute,  but  above 
this  speed  the  respiration-rate  increased  more  rapidly.  Thus,  the 
increment  above  the  standing  rate  was  increased  1.9  respirations  for 


EXPERIMENTS   WITH    HORIZONTAL   WALKING. 


161 


an  increase  in  average  speed  from  43.8  to  77.5  meters  per  minute,  while 
with  an  increase  in  speed  from  this  point  to  96.0  meters  per  minute,  the 
increment  in  the  respiration  over  the  standing  increased  3.3  respira- 
tions. 

The  respiration-rate  of  E.  L.  F.  was  of  marked  peculiarity  on  the  two 
days  of  January  22  and  24  as  compared  with  the  rate  on  January  21. 
(See  table  12,  p.  68.)  On  all  three  days  the  respiration  tracings 
shown  on  the  kymograph  for  the  standing  periods  were  normal  and  not 
dissimilar  to  those  of  the  other  subjects.  This  was  also  the  case  with 
his  walking  periods  on  January  21,  but  in  his  walking  periods  of 
January  22  and  24  there  was  a  marked  change,  the  rates  falling  to  5  to 
8  per  minute,  while  the  volume  per  respiration  (unreduced),  as  meas- 

TABLE  44. — Increments  in  various  physiological  factors  due  to  walking  on  a  level  in  experiments 
without  food.     (Values  per  minute.) 


Nn   nf 

Respiration-rate. 

Pulmonary  ventilation 
(reduced). 

I1!  U.    VI 

Average 

Subject  and  speed. 

experi- 
mental 
periods. 

distance 
walked. 

Average. 

Increase 
over 

Average. 

Increase 
over 

standing. 

standing 

A.  J.  O.: 

meters. 

liters. 

liters. 

60  to  65  meters  .  . 

6 

63.0 

23.8 

2.0 

16.0 

8.2 

H.  R.  R.: 

60  to  65  meters  .  . 

11 

60.9 

17.3 

1.8 

14.8 

7.8 

65  to  70  meters  .  . 

4 

67.1 

18.0 

2.5 

16.4 

9.4 

T.  H.  H.: 

60  to  65  meters  .  . 

7 

63.2 

14.2 

1.3 

11.4 

4.9 

65  to  70  meters  .  . 

14 

67.1 

14.6 

1.7 

11.4 

4.9 

W.  K.: 

55  to  60  meters  .  . 

10 

58.3 

21.3 

.2 

11.1 

4.6 

60  to  65  meters  .  . 

19 

62.9 

20.8 

-.3 

10.8 

4.3 

65  to  70  meters  .  . 

20 

66.6 

22.4 

1.3 

11.7 

5.2 

E.  D.  B.: 

35  to    40  meters  . 

6 

36.2 

19.2 

3.8 

11.3 

2.2 

40  to    45  meters  . 

13 

43.8 

18.7 

3.3 

11.1 

2.0 

45  to    50  meters  . 

22 

46.3 

19.5 

4.1 

11.5 

2.4 

50  to    55  meters  . 

22 

53.7 

20.7 

5.3 

13.3 

4.2 

55  to    60  meters  . 

18 

56.5 

20.0 

4.6 

14.5 

5.4 

60  to    65  meters  . 

30 

63.9 

19.4 

4.0 

14.2 

5.1 

65  to    70  meters  . 

15 

66.8 

19.9 

4.5 

14.0 

4.9 

70  to    75  meters  . 

26 

72.2 

19.0 

3.6 

13.9 

4.8 

75  to    80  meters  . 

37 

77.5 

20.6 

5.2 

15.1 

6.0 

85  to    90  meters  . 

4 

88.5 

24.1 

8.7 

18.5 

9.4 

90  to  100  meters. 

5 

96.0 

23.9 

8.5 

20.1 

11.0 

J.  H.  G.: 

50  to  55  meters  .  . 

3 

53.9 

19.4 

3.1 

16.1 

5.5 

55  to  60  meters  .  . 

6 

55.4 

18.7 

2.4 

15.5 

4.9 

E.  L.  F.  : 

45  to  50  meters  .  . 

3 

49.1 

5.4 

-9.6 

13.6 

3.0 

50  to  55  meters  .  . 

6 

52.6 

12.3 

-2.7 

14.5 

3.9 

H.  M.  S.: 

45  to  50  meters  .  . 

3 

42.8 

17.5 

.6 

12.1 

2.1 

50  to  55  meters  .  . 

3 

52.8 

17.3 

.4 

12.7 

2.7 

162 


METABOLISM   DURING   WALKING. 


TABLE  44. — Increments  in  various  physiological  factors  due  to  walking  on  a  level  in  experiments 
without  food.     (Values  per  minute.) — Continued. 


Subject  and  speed. 

Pulse-rate. 

Body-temperature. 

Blood-pressure. 

Average 

Increase 
over 
standing. 

Average. 

Increase 
over 
standing. 

Average. 

Increase 
over 
standing. 

A.  J.  0.: 

60  to  65  meters 

°C. 

°C. 

mm. 

mm. 

H.  R.  R.: 

60  to  65  meters  .  . 
65  to  70  meters  .  . 
T.  H.  H.: 
60  to  65  meters  .  . 
65  to  70  meters  .  . 
W.  K.: 
55  to  60  meters  .  . 
60  to  65  meters  .  . 
65  to  70  meters  .  . 
E.  D.  B.: 
35  to   40  meters  . 
40  to    45  meters  . 
45  to    50  meters  . 
50  to    55  meters  . 
55  to    60  meters  . 
60  to   65  meters  . 
65  to    70  meters  . 
70  to    75  meters  . 
75  to    80  meters  . 
85  to   90  meters. 
90  to  100  meters. 
J.  H.  G.: 
50  to  55  meters  .  . 
55  to  60  meters  .  . 
E.  L.  F.: 
45  to  50  meters  .  . 
50  to  55  meters  .  . 
H.  M.S.: 
45  to  50  meters  .  . 
50  to  55  meters  .  . 

104 
110 

100 
96 

75 

85 
84 

72 
74 
68 
77 
76 
95 
78 
82 
85 
94 
98 

98 
94 

100 

89 

93 

88 

11 
17 

4 
0 

-4 
6 
5 

-6 
-4 

-10 
j 

-2 
17 
0 
4 
7 
16 
20 

-12 
-16 

-7 
-18 

1 
-  4 

36.90 

0.01 

120 

3 

37.03 
36.84 
37.18 
37.13 
36.90 
37.12 
37.25 
37.28 

.14 
-.05 
.29 
.24 
.01 
.23 
.36 
.39 

125 
124 
120 
119 
122 
125 
130 
130 

8 
7 
3 
2 
5 
8 
13 
13 

. 

ured  by  the  kymograph  tracings,  was  increased  to  not  far  from  3 
liters  per  respiration  or  approximately  three  times  that  of  the  average 
for  the  other  subjects.  The  respiration-rates  in  the  last  two  days  were 
undoubtedly  abnormal,  although  E.  L.  F.  reported  that  he  was  uncon- 
scious of  making  any  effort  and  was  not  aware  of  breathing  other  than 
normally.  He  thought  that  once  during  the  experiment  his  throat  felt 
rather  dry,  and  stated  that  at  one  time  he  had  been  troubled  with 
asthma. 

PULMONARY  VENTILATION  DURING  HORIZONTAL  WALKING. 

The  data  in  tables  8  to  12  show  that  the  pulmonary  ventilation  for  a 
given  speed  was  fairly  uniform,  also  that  there  was  no  marked  change 
from  period  to  period  during  the  day.  The  percentage  increases  over 
the  average  standing  rate  for  the  various  speed  groups  are  given  for 


EXPERIMENTS   WITH   HORIZONTAL   WALKING. 


163 


E.  D.  B.  in  table  45.  The  average  percentage  changes  in  the  ventila- 
tion for  all  of  the  subjects,  as  calculated  for  approximately  the  same 
speed,  i.  e.,  52.6  to  63.2  meters  per  minute,  are  likewise  given  in 
table  45.  It  is  apparent  from  these  percentages  that  the  differences 
between  the  individual  subjects  are  very  great.  Even  if  we  exclude 
those  subjects  for  whom  we  have  the  least  data  and  compare  the  results 
for  W.  K.  and  E.  D.  B.,  with  whom  the  greatest  number  of  experiments 
were  made,  we  still  find  a  ra,nge  of  from  59  to  7 1  per  cent  for  practically 
the  same  speed  of  walking. 

The  effect  of  the  increase  in  speed  upon  the  ventilation  for  the  indi- 
vidual subjects  can  be  seen  from  the  group  averages  in  table  44. 
H.  R.  R.  shows  an  increase,  T.  H.  H.  shows  no  change,  while  with 
W.  K.  there  was  a  slight  increase.  With  E.  D.  B.  there  was  practically 
no  change  for  the  three  lower  speeds;  for  the  speeds  between  56.5  and 
72.2  meters  per  minute  there  was  an  increase  over  the  preceding  groups, 
but  within  this  range  the  ventilation  was  quite  constant,  while  above 
this  speed  the  rate  of  increase  was  much  greater.  This  is  seen  in  table 
45,  in  which  the  increase  in  the  ventilation  over  the  standing  is  figured 
percentagewise  for  this  subject  for  the  various  speed-groups  given  in 
table  44.  The  slight  difference  in  the  percentage  for  the  moderate 
speeds  with  the  marked  increase  for  speeds  above  77.5  meters  is  here 
very  apparent. 

TABLE  45. — Percentage  increase  in  pulmonary  ventilation  over  standing  requirement  with 
E.  D.  B.,  at  increasing  speeds  of  horizontal  walking,  and  for  all  subjects  at  approxi- 
mately the  same  speed  (53  to  68  meters).  (Values  per  minute.) 


Percentage 

Percentage 

Subjects. 

Average 
speed. 

increase 
over 

Subjects. 

Average 
speed. 

increase 
over 

standing. 

standing. 

meters. 

p.  ct. 

meters. 

p.  ct. 

E.  D.B.... 

36.2 

24 

A.  J.  O..    . 

63.0 

100 

43.8 

22 

H.R.R..   . 

60.9 

80 

46.3 

26 

T.H.H..   . 

63.2 

75 

53.7 

46 

W.  K 

58.3 

71 

56.5 

59 

E.  D.B..    . 

56.5 

59 

63.9 

56 

J.  H.  G..    . 

53.9 

52 

66.8 

54 

E.  L.  F..    . 

52.6 

37 

72.2 

53 

H.M.S..   . 

52.8 

27 

77.5 

'  67 

88.5 

103 

96.0 

122 

PULSE-RATE  DURING  HORIZONTAL  WALKING. 

The  belief  that  there  is  a  relationship  between  the  pulse-rate  and 
the  degree  of  metabolism  for  the  same  subject  has  been  expressed 
in  previous  reports  from  this  Laboratory,1  and  for  a  number  of  years 


Benedict  and  Cathcart,  Carnegie  Inst.  Wash.  Pub.  No.  187,  1913,  pp.  153  and  172;  Benedict 
and  Murschhauser,  Carnegie  Inst.  Wash.  Pub.  No.  231,  1915,  p.  69;  Harris  and  Benedict,  Carnegie 
Inst.  Wash.  Pub.  No.  279,  1919,  p.  79. 


164  METABOLISM   DURING   WALKING. 

it  has  been  the  practice  to  record  carefully  the  pulse-rates  in  all  the 
basal  metabolism  measurements  carried  out  here.  Such  records  were 
accordingly  made  in  this  research. 

The  detailed  data  of  the  pulse-rates  of  the  subjects  during  the  hori- 
zontal walking  periods,  as  obtained  by  the  method  already  described, 
are  given  chronologically  in  tables  8  to  12.  It  should  be  stated  again, 
however,  that  the  difficulties  which  were  experienced  in  this  initial 
work  of  recording  the  pulse-rate  have  made  the  data  incomplete. 
Accordingly,  although  the  rates  as  reported  for  the  individual  periods 
are,  in  a  large  majority  of  cases,  average  values  determined  at  three 
intervals  about  equally  distributed  throughout  the  period,  nevertheless, 
there  are  individual  averages  which  represent  only  one  or  two  readings. 

As  the  pulse-rates  tended  to  increase  during  the  walking  periods, 
the  average  value  would  naturally  be  affected  by  the  failure  to  secure 
either  the  first  or  the  last  reading,  and  this  fact  undoubtedly  explains 
some  of  the  irregularities.  Although  many  measurements  of  the 
pulse-rate  have  been  made  in  connection  with  studies  on  muscular 
exercise,  the  difficulties  of  actually  recording  the  pulse  by  the  methods 
commonly  used  are  great  when  the  subject  is  exercising,  and  most  of 
the  records  previously  reported  have  therefore  been  made  immediately 
at  the  end  of  and  not  during  the  period  of  exercise.1 

As  the  pulse-rate  is  subject  to  sudden  and  wide  fluctuations  due  to 
mental  and  physical  conditions,  uniformity  in  results  is  perhaps  more 
than  should  be  expected,  and  only  comparisons  from  much  larger 
groups  of  results  than  here  obtained  could  yield  very  definite  conclu- 
sions. For  this  reason  the  speed  groups  in  table  35  and  the  summary 
in  table  44  give,  perhaps,  the  most  satisfactory  method  for  comparing 
the  material  at  hand.  However,  the  results  recorded  in  tables  8  to  12 
show  one  point  very  clearly,  namely,  that  the  pulse-rates  tended  to 
increase  as  the  periods  continued  during  the  forenoon. 

From  both  tables  35  and  44  it  may  be  seen  that  H.  R.  R.  had  a 
high  pulse-rate  as  compared  with  other  men  walking  at  similar  speeds. 
With  this  subject  the  highest  pulse-rate  and  highest  metabolism  were 
obtained  on  his  first  day  of  walking.  (See  table  8,  p.  56.)  The  two 
averages  for  H.  R.  R.  in  tables  35  and  44  show  that  his  pulse-rate  was 
increased  6  beats  for  an  average  increase  in  speed  of  6.2  meters  per  min- 
ute. T.  H.  H.,  however,  shows  the  reverse,  although  the  average  for 
the  heat-output  increased.  (See  table  35.)  W.  K.  had  an  increase  in 
pulse-rate  between  the  first  and  second  speed-groups,  but  a  drop  of 
1  beat  between  the  second  and  third  groups.  These  figures  of  W.  K. 
do  not  cover  the  earlier  days  of  his  walking  experiments,  while  the 

*A  striking  exception  is  that  too  little  known  but  admirable  research  of  W.  P.  Bowen  (Bowen, 
A  study  of  the  pulse-rate  in  man  as  modified  by  muscular  work.  Contributions  to  Medical 
Research,  dedicated  to  Victor  Clarence  Vaughan  by  colleagues  and  former  students  of  the  De- 
partment of  Medicine  and  Surgery  of  the  University  of  Michigan,  Ann  Arbor,  Michigan,  June, 
1903,  p.  462.) 


EXPERIMENTS   WITH   HORIZONTAL   WALKING.  165 

average  speeds,  as  well,  indeed,  as  the  average  metabolism  (see  table 
35),  are  from  the  full  quota  of  experiments.  The  relationship  is  but 
little  changed,  however,  if  the  speed  and  metabolism  averages  are 
based  on  the  same  days  for  which  the  pulse-records  are  available. 
The  variations  which  may  occur  in  the  pulse-rates  for  the  same  sub- 
ject are  seen  by  comparing  the  rates  of  W.  K.  for  March  17  and  25. 
The  speed  of  walking  on  these  days  was  almost  identical  and  the  period 
pulse-rates  on  each  day  were  uniform,  and  yet  there  is  a  difference 
between  the  pulse-rates  on  the  two  days  of  17  beats  per  minute.  (See 
table  10,  p.  58.) 

With  E.  D.  B.  it  is  seen  from  table  44  that  with  the  lower  speeds  of 
the  first  three  groups  the  average  pulse-rate  is  71  and  for  the  next  two 
groups  with  higher  speed  the  average  is  77.  Omitting  the  group  for 
60  to  65  meters  per  minute,  we  find  that  the  three  speed-groups  from 
65  to  80  meters  per  minute  have  an  average  pulse-rate  of  82,  and  the 
last  two  groups  an  average  pulse-rate  of  96.  Thus,  when  the  subject 
changed  from  the  lowest  average  speed  of  36.2  meters  per  minute  to  an 
average  of  77.5  meters  per  minute,  with  an  increase  in  distance  walked 
of  41  meters  per  minute,  the  increment  in  the  pulse-rate  was  but  13 
beats,  whereas  a  further  increase  in  speed  of  only  19  meters  per  minute 
produced  exactly  the  same  increment  in  the  pulse-rate,  i.  e.,  13  beats. 
This  marked  change  in  rate  of  increase  of  the  pulse  at  80  to  85  meters 
per  minute  as  a  result  of  increase  in  speed  is  in  keeping  with  the  incre- 
ment found  in  the  total  heat-output  for  walking  above  this  optimum 
speed. 

The  high  pulse-rate  for  the  group  60  to  65  meters  per  minute  is  due 
to  the  pulse-records  for  January  31  and  February  1,  which,  it  will  be 
recalled,  were  the  first  days  following  the  return  of  E.  D.  B.  from  his 
absence  on  account  of  his  lameness.  In  this  group  is  one  record  on 
March  30  of  a  pulse-rate  of  82,  which  is  more  in  conformity  with  the 
pulse-rates  of  contiguous  speed-groups,  although  this  value  is  still 
somewhat  high.  With  the  three  subjects,  J.  H.  G.,  E.  L.  F.,  and 
H.  M.  S.,  there  is  a,  fall  in  the  average  pulse-rate  with  the  increase  in 
the  speed  of  walking.  This  is  probably  due  to  the  fact  that  the  sub- 
jects were  untrained  and  that  the  lower  speeds  were  ordinarily  used  on 
the  first  day,  when  a  greater  mental  stimulus  would  naturally  produce 
a  higher  pulse-rate.  The  fact,  therefore,  that  these  three  men  all 
showed  a  lowering  of  the  pulse-rate  with  increase  in  speed  is  not,  under 
the  circumstances,  so  significant. 

COMPARISON  OP  PTJLSE-RATE  DURING  STANDING  WITH  THAT  DURING  HORIZONTAL  WALKING. 

The  effect  upon  the  pulse-rate  of  the  activity  of  level  walking,  as 
obtained  from  a  comparison  of  these  group  averages  with  the  standing 
average,  may  be  seen  hi  table  44.  With  the  lower  speeds  of  W.  K.  and 
E.  D.  B.  and  in  all  but  one  instance  with  the  three  laboratory  men, 


166 


METABOLISM   DURING  WALKING. 


J.  H.  G.,  E.  L.  F.,  and  H.  M.  S.,  at  similar  speeds,  the  pulse-rate  during 
walking  was  lower  than  in  the  standing  periods.  The  difference  is  in 
many  cases  pronounced  and  implies  that  even  with  a  trained  subject 
like  E.  D.  B.  it  is  possible  to  have  a  lower  pulse  during  moderate  walk- 
ing than  when  standing.  If,  instead  of  using  the  average  group  values, 
the  pulse-rates  on  the  days  when  both  standing  and  horizontal  walking 
experiments  were  successively  made  are  compared  by  plotting  the  con- 


Fio.  12. — Typical  pulse-rate  curves  for  E.  D.  B.  and  W.  K.  during  standing  and  horizontal- 
walking  experiments.  (Values  per  minute.) 

Speed  of  walking  indicated  in  meters.  Change  of  conditions  shown  by  arrows  and  numbers:  1, 
subject  sitting;  2,  standing;  3,  walking.  Records  made  in  the  experimental  periods 
represented  by  black  points.  Curve  A,  April  13;  B,  April  5;  C,  March  30;  D,  March  31; 
E,  April  4,  1916;  F,  March  18;  G,  March  17,  1915. 

tinuous  pulse-readings  during  the  forenoon,  the  relationship  between 
standing  and  walking  values  will  be  more  clearly  shown.  A  few  curves 
for  W.  K.  and  E.  D.  B.  have  been  plotted  in  figure  12.  Here  it  is 
seen  that  whereas  the  pulse-rate  tended  to  increase  during  the  walking 
periods,  during  the  standing  periods  there  was  considerable  variation; 
also,  that  as  a  rule  the  increase  was  marked  when  the  subject  changed 


EXPERIMENTS  WITH   HORIZONTAL   WALKING.  167 

from  standing  to  walking,  although  the  reverse  was  sometimes  true. 
The  most  striking  point  is  the  wide  difference  in  the  pulse-rate  which 
may  be  expected  from  the  same  subject,  even  when  the  conditions  are 
practically  the  same.  It  would  appear  as  though  the  pulse  is  so  sensi- 
tive and  variable,  not  only  from  day  to  day,  but  from  minute  to  minute, 
that  any  uniform  figures  are  not  to  be  expected,  and  even  with  the  use 
of  experienced  and  well-trained  subjects  the  conditions  of  the  experi- 
ments must  be  carried  out  with  the  least  possible  opportunity  for 
mental  disturbance  during  the  time  of  the  experiment. 

In  a  recent  study  in  the  Nutrition  Laboratory,1  some  pulse  measure- 
ments were  made  with  a  group  of  12  normal  young  men,  both  while 
they  were  standing  and  while  they  were  walking  on  a  level  at  a  rate 
of  70  meters  per  minute.  The  average  standing  value  for  this  group 
was  79  pulse-beats  per  minute,  while  for  walking  the  average  rate 
varied  from  88  to  85  beats  between  the  first  and  twelfth  minutes  of 
walking.  The  standing  pulse-rates  of  W.  K.  and  E.  D.  B.  are  thus 
in  keeping  with  this  group  average  for  standing,  while  the  rates  for 
walking  at  this  speed  are  somewhat  lower.  In  the  case  of  the  group 
of  12  men,  it  can  not  be  said  that  the  subjects  were  particularly 
trained  for  these  experiments,  though  they  were  physically  active  and 
athletic  young  men. 

Benedict  and  Murschhauser2  report  that  on  two  days  their  subject 
showed  a  lower  pulse-rate  during  level  walking  than  in  the  standing 
portion  of  the  experiment,  in  spite  of  the  fact  that  the  metabolism  was 
increased  over  100  per  cent  above  the  basal  requirements.  This 
observation  was  so  contrary  to  the  general  relation  between  the  pulse- 
rate  and  the  metabolism  that  further  tests  were  made  at  the  Nutrition 
Laboratory  and  similar  results  found.  In  later  work3  with  a  group 
of  5  normal  men  this  observation  was  not  confirmed. 

In  a  careful  study  of  the  records  of  W.  K.  and  E.  D.  B.  in  the  present 
research  and  the  exclusion  of  all  cases  in  which  there  might  appear  to 
be  some  disturbing  influence  which  produced  an  unduly  high  pulse-rate 
for  the  standing  position,  we  have  found  the  instances  given  hi  table  46 
of  pulse-rates  that  are  lower  during  level  walking  at  moderate  speed 
than  during  the  preceding  time  when  the  subject  was  standing.  Thus, 
W.  K.,  during  the  standing  period  on  March  16,  in  three  counts  from 
9h  7m  a.  m.  to  9h  19111  a.  m.,  had  a  pulse-rate  ranging  from  77.7  to 
84.1  beats.  The  subject  began  walking  at  10h  45m  a.  m.  at  a  speed  of 
59  meters  per  minute.  After  he  had  walked  14  minutes,  his  pulse-rate 
was  72.7  and  later  74.5.  In  this  particular  instance,  the  records  for 
standing  were  obtained  in  the  first  period  of  the  experiment,  while  those 
for  walking  were  for  the  fourth  period  on  that  day;  for  the  intervening 

Benedict,  Miles,  Roth,  and  Smith,  Carnegie  Inst.  Wash.  Pub.  No.  280,  1919,  p.  442. 
^Benedict  and  Murschhauser,  Carnegie  Inst.  Wash.  Pub.  No.  231,  1915,  pp.  54,  55,  and  85. 
"Benedict,  Miles,  Roth,  and  Smith,  Carnegie  Inst.  Wash.  Pub.  No.  280,  1919,  p.  451. 


168 


METABOLISM   DURING   WALKING. 


TABLE  46. — Records  showing  decrease  in  pulse-rate  of  W.  K.  and  E.  D.  B.  in  changing  from  standing 
position  to  horizontal  walking  in  experiments  without  food.     (Values  per  minute.) 


Subject,  date,  and 
time. 

Conditions,  and  rate  of 
walking  per  minute. 

Pulse- 
rate. 

Subject,  date,  and 
time. 

Conditions,  and  rate  of 
walking  per  minute. 

Pulse- 
rate. 

W.  K. 
Mar.  16: 

ghQyrn  g   jjj 

77.7 

E.  D.  B.  (Cont.) 
Mar.  29  (Cont.) 
10b56m  a.  m.  .  . 

Standing  

86.3 

0  12    a  m 

Do  

84.1 

11  10   a.m... 

Walking  began;  58  meters  . 

9  19    a  m 

Do                   

81.9 

1  1  40    a.  m.  .  . 

Walking  

83  6 

in    d.^      am1 

1  1  49   a.  m.  .  . 

.    ...   Do.  . 

87  7 

10  59   a  m 

Walking       

72.7 

Mar.  30: 

11  04   a  m 

Do  

74.5 

10h51ma.  m..  . 

Standing  

78.2 

Mar    17- 

11  01    a.  m.  .  . 

Do  

87  3 

10h26m  a  m 

Standing            

74.8 

11  10    a.  m.  .  . 

Walking  began  ;  69  meters  . 

10  30   a  m 

Do            

77.2 

1  1  56   a.  m.  .  . 

Walking  

83.4 

10  34    am 

Do.           

77.6 

12  01    p.  m.  .  . 

Do  

82  6 

10  48   a.  m.  .  . 
11  05   a  m 

Walking  began  ;  67  meters  . 

72.8 

Mar.  31: 
10h51ma.  m.  .  . 

Standing  

80  7 

11  10   am 

Do                     

75.0 

10  56    a.  m.  .  . 

Do  

77  4 

11  15    am 

Do 

76.5 

11  01    a.  m.  .  . 

Do  

74  6 

Mar.  18: 
10h20ma  m 

84.2 

11  34    a.  m..  . 
11  55    a.  m. 

Walking  began;  55  meters  . 
Walking  

65  8 

10  24    am 

Do 

83.4 

12  00   p.  m. 

Do  .    .  . 

67  3 

10  29   am 

Do            

85.6 

12  04   p.  m.  .  . 

Do  

70  7 

10  51    a.  m.  .  . 
10  53   am 

Walking  began;  63  meters  . 
Walking  (prelim.)  

72.4 

Apr.  1: 
10h34m  a.  m.  .  . 

Standing  

72  4 

10  58    am 

Do                        

73.6 

10  39    a.  m.  .  . 

Do  

83  6 

10  43    a.  m. 

Do  

81  0 

E.  D.  B. 
Dec.  6.: 

11  04   a.m... 
11  22    a.  m.  .  . 

Walking  began  ;  53  meters  . 
Walking  

71  3 

S^o™  a.  m. 

Standing  (prelim.)  

66.7 

Apr.  3: 

8  58    a.  m. 

W^alking  began  ;  45  meters  . 

10h31ma.  m.  .  . 

Standing  

71  8 

9  23     a.  m. 

Walking                    

61.6 

10  35    a.  m.  .  . 

Do...'.  

79  2 

9  33    a.  m. 

Do. 

64.4 

10  40   a.  m.  .  . 

Do  

78  4 

Jan.  31: 
10h04m  a.  m.  . 

Standing  

83.7 

10  56   a.  m.  .  . 
11  16   a.  m.  .  . 

Walking  began;  35  meters  . 
Walking  

63  5 

10  08    a.m.. 

.    .    .   Do  

89.7 

1  1  22    a.  m.  .  . 

Do  

69  2 

10  13   a.  m.  .  . 

.  .   Do  

90.2 

11  26  a.  m.  .  . 

Do  

72  7 

10  22    a.  m.  .  . 
10  28    a.  m.  .  . 

Walking  began;  62  meters  . 
Walking  (prfilirn,)  ..,.,.,. 

87.5 

Apr.  4: 
10h43ma.  m..  . 

Standing  

84.8 

Feb.  1  : 

10  47    a.  m.  . 

Do  

85  6 

9h39ma.  m.  .  . 

Standing  

93.3 

11  08   a.  m.  .  . 

Walking  began;  36  meters  . 

9  45    a.  m.  .  . 

Do  

92.8 

11  26    a.  m.  .  . 

Walking  

65  4 

9  48    a.  m.  .  . 

Do  .». 

93.3 

11  30   a.  m.  .  . 

Do  

71  5 

10  00   a.  m.  .  . 

Walking  began;  63  meters  . 

11  34   a.m... 

Do  

69  2 

10  03   a.  m.  .  . 

Walking  (prelim.)  

93.4 

Apr.  5: 

Mar.  22: 

lO^l^a.m... 

Standing  

89.9 

Ilh15ma.m... 

Standing  

72.5 

10  35   a.  m.  .  . 

.    .     Do. 

89  3 

11  29    a.m... 

Do  

84.0 

10  40   a.  m. 

Do. 

90  2 

11  30   a.m... 
11  33    a.  m..  . 

Walking  began  ;  75  meters  . 
Walking  

76.5 

10  57   a.m... 
11  13   a.m... 

Walking  began;  77  meters  . 
Walking  

84  9 

11  37   a.m... 

Do  

83.8 

11  17   a.m... 

Do  

85  0 

Mar.  29: 

11  23   a.  m..  . 

Do     

90  0 

10h50ma.m... 

Standing  

80.7 

10  53   a.  m.  .  . 

Do  

80.7 

JNo  records  for  periods  II  and  III. 


EXPERIMENTS   WITH   HORIZONTAL   WALKING.  169 

two  periods  no  record  was  available.  On  March  17  the  standing  rate 
of  74.8  to  77.6  was  followed  by  a  rate  of  72.8  after  17  minutes  of  walk- 
ing, which  rose  in  10  minutes  to  76.5.  A  more  pronounced  change  is 
seen  in  the  records  for  March  18,  in  which  case  the  pulse-rate  after  the 
subject  had  walked  7  minutes  was  73.6  as  compared  with  a  standing 
rate  of  85.6  at  the  end  of  the  standing  period. 

With  E.  D.  B.  similar  cases  were  found.  The  records  for  February 
1  have  been  included  in  the  table  to  show  that  while  the  standing 
pulse  was  abnormally  high,  the  pulse  in  the  preliminary  period  of 
walking  was  also  high,  although  no  higher  than  that  for  standing. 
The  rates  of  March  29  and  30  show  that  though  the  first  walking  rate 
was  higher  than  the  first  standing  rate,  it  was  nevertheless  lower  than 
the  final  standing  rate,  even  though  the  subject  had  walked  30  and 
46  minutes  at  a  speed  of  58  and  69  meters  per  minute,  respectively, 
between  the  two  sets  of  pulse-records. 

It  is  thus  evident  that  these  records  confirm  the  earlier  observations 
of  Benedict  and  Murschhauser.  This  fall  is  so  pronounced  as  to  justify 
the  statement  that  a  change  from  standing  to  walking  at  moderate 
speeds,  i.  e.,  35  to  75  meters  per  minute,  is  in  many  instances  accom- 
panied by  a  decrease  in  pulse-rate,  although  the  metabolism  may  si- 
multaneously be  doubled  or  more.  In  many  of  the  records  in  table  46, 
a  pulse-rate  after  a  considerable  period  of  forced  quiescence  is  compared 
with  that  found  early  in  a  period  of  walking.  It  may  be  suggested 
that  the  change  in  walking  was  possibly  agreeable  to  the  subject 
and  thus  in  part  account  for  the  apparent  anomaly.  This  does  not, 
however,  explain  such  definite  records  as,  for  instance,  those  for  E.  D.  B. 
on  March  31,  when  all  of  the  walking-rates  were  clearly  lower  than 
the  standing  rates.  The  fact  that  these  lower  rates  were  found  after 
the  subject  had  been  walking  in  some  cases  from  15  to  20  minutes 
precludes  the  suggestion  put  forth  by  Benedict,  Miles,  Roth,  and  Smith1 
that  possibly  the  low  pulse-rates  found  by  Benedict  and  Murschhauser 
had  been  counted  during  a  moment  of  pulse-reaction  from  the  first 
stimulus  of  walking.  The  fact  that  the  pulse-rates  for  walking  on  a 
level  at  a  moderate  speed  can  be  maintained  at  a  lower  rate  than  when 
the  subject  is  standing  is  of  prime  physiological  interest  and  warrants 
further  study. 

RELATIONSHIP  OF  OXYGEN  CONSUMPTION,  PULSE-RATE,  AND  PULMONARY  VENTILATION 
DURING  HORIZONTAL  WALKING. 

The  relationship  between  the  oxygen  consumption  and  the  heat-out- 
put of  the  body  is  so  close  that  the  oxygen  consumption  may,  to  a 
certain  extent,  be  taken  as  a  measure  of  the  heat-output.  It  has  also 
been  shown  by  Boothby2  that  the  oxygen  consumption  and  the  ven- 

^enedict,  Miles,  Roth,  and  Smith,  Carnegie  Inat.  Wash.  Pub.  No.  280,  1919,  p.  451. 
'Boothby,  Am.  Journ.  Physiol.,  1915,  37,  p.  383. 


170 


METABOLISM   DURING   WALKING. 


tilation  are  linear  functions,  and  Means  and  Newburgh1  have  shown 
that  the  same  is  true  for  the  oxygen  consumption  and  ventilation  in 
relation  to  work. 

In  figure  13  curves  have  been  plotted  for  E.  D.  B.  for  the  total  heat- 
output,  oxygen  consumption,  pulmonary  ventilation,  respiration,  and 
pulse-rate  in  relation  to  the  horizontal  kilogrammeters  (h.  kg.  m.) 
of  work  done,  using  the  average  values  for  the  5-meter  speed-groups 
in  table  35,  page  144.  These  curves  show  how  closely  the  heat-output 
and  the  oxygen  consumption  follow  each  other  with  the  increasing 
amount  of  work  done.  They  also  show  a  constant  rate  of  oxygen  con- 
sumption up  to  the  point  of  2,720  h.  kg.  m.  Above  this  the  oxygen 
increases  at  a  uniform  rate  with  the  work  done,  if  we  except  the  h  igh  point 
of  3,840  h.  kg.  m.,  which  represents  the  work  done  for  the  most  part  in 
October  when  the  experiments  were  begun  with  this  subject,  and  he 
was  unused  to  the  apparatus.  The  curve  above  4,560  h.  kg.  m.  is 
somewhat  more  sharply  ascendant  than  below  that  point,  but  there  is 
no  marked  alteration  in  the  oxygen  consumption. 


P      R 


Liter* 
22 


100 

90  24  20 

80  22    18 

K>  20    16 

18    14 

12 

10 


BE 
KKfl.m».   2400 


360O          4000          4400  4800.        5200 


),     v^ais. 
900    4.5 

800  4.0 

700  3.5 

600  3.0 

500  2.5 


I400    2.O 

6000 


FIG.  13. — Total  heat-output  (cals.),  oxygen  consumption  (Oj),  pulmonary  ventilation  (V), 
respiration-rate  (R),  and  pulse-rate  (P),  of  E.  D.  B.  and  W.  K.,  referred  to  horizontal  kilo- 
grammeters (h.  kg.  m.)  for  experiments  with  subjects  walking  on  a  level  at  different  speeds. 
(Values  per  minute.) 

The  supply  of  oxygen  necessary  to  meet  the  increased  needs  of  the 
body  during  work  is  determined  by  a  number  of  factors,  of  which  pul- 
monary ventilation  and  pulse  are  of  special  importance.  The  pulse 
and  ventilation  curves  should  therefore  be  compared  in  relation  to  the 
oxygen  consumption.  Like  the  curve  for  oxygen,  the  two  curves  for 
pulse-rate  and  ventilation  show  no  notable  changes  with  the  smaller 
amounts  of  work.  For  the  larger  amounts  the  increase  in  the  oxygen 
consumption  is  followed  more  closely  by  the  pulse-curve  than  by  the 
ventilation  curve,  as  the  latter  does  not  increase,  butvremains  practi- 
cally uniform  between  3,400  and  4,300  h.  kg.  m.  This  would  indicate 
that  the  necessary  oxygen  for  the  increased  needs  of  the  body  is  met 

^eans  and  Newburgh,  Journ.  Pharm.  and  Exp.  Therapeutics,  1915,  7,  p.  449. 


EXPERIMENTS  WITH   HORIZONTAL   WALKING.  171 

by  the  increase  in  the  pulse-rate  and  its  attendant  blood-flow  if  that 
factor  were  known,  while  a  ventilation  of  14  liters  per  minute  was 
sufficient  to  meet  the  needs  during  this  range  of  increasing  work. 
The  high  oxygen  consumption  of  633  c.  c.  at  3,840  h.  kg.  m.  referred  to 
hi  the  previous  paragraph  is  accompanied  by  an  increase  ha  pulse- 
rate,  but  no  change  is  evident  in  the  ventilation  at  this  tune. 
Beyond  4,292  h.  kg.  m.  the  ventilation  curve  shows  a  marked  increase, 
while  the  increase  hi  the  pulse  is  less  in  degree,  indicating  that  here 
the  demand  for  oxygen  was  not  met  by  an  increase  in  the  pulse  so 
much  as  by  a  larger  pulmonary  ventilation.  The  respiration-rate  and 
the  volume  per  inspiration  determine  the  pulmonary  ventilation. 
A  reference  to  the  curve  for  the  respiration-rate  shows  that  up  to  4,292 
h.  kg.  m.  the  increase  in  the  pulmonary  ventilation  must  come  from  an 
increase  in  volume  per  inspiration  rather  than  from  any  increase  in  the 
respiration-rate.  Beyond  4,292  h.  kg.  m.  the  respiration-rate  shows  a 
sharp  increase  in  keeping  with  the  ventilation.  With  the  data  in  hand, 
we  are  not  able  to  discuss  that  portion  of  the  compensation  due  to  an 
increase  in  the  oxygen-carrying  power  of  the  blood  which  is  caused  by 
an  increase  in  volume  of  the  heart-output.  It  is  evident,  however, 
that  in  a  change  from  standing  to  walking  there  is  possible  an  actual 
decrease  in  pulse-rate  with  a  simultaneous  increase  of  100  or  more  per 
cent  in  the  oxygen  consumption.  This  physiological  fact,  even  though 
incompletely  explained  at  this  time,  yet  suggests  many  topics  for 
experimentation. 

The  curves  for  the  same  factors  for  W.  K.  are  also  given  in  figure  13, 
and  though  the  range  in  the  amount  of  work  is  much  less,  the  same 
characteristics  are  shown  by  his  curves,  namely,  for  the  amount  of 
work  done,  that  the  oxygen  consumption  and  heat-output  run  uniformly 
with  the  increase  in  the  horizontal  kilogrammeters  of  work,  that  the 
ventilation  shows  no  increase  for  these  moderate  demands,  but  that  the 
increase  hi  the  pulse-rate  is  responsible  for  the  increase  in  the  oxygen- 
supply.  The  respiration-rate  for  W.  K.,  in  contrast  to  that  of  E.  D.  B., 
shows  an  increase  with  a  constant  ventilation,  indicating  a  change  to  a 
smaller  volume  per  inspiration. 


172 


METABOLISM   DURING   WALKING. 


BODY-TEMPERATURE  DURING  HORIZONTAL  WALKING. 

There  were  15  days  of  horizontal  walking  on  which  body- temperature 
measurements  were  made  with  E.  D.  B.,  including  hi  all  41  experimen- 
tal periods .  These  walking  experiments  were  all  preceded  by  standing 
experiments  in  which  the  body-temperature  was  likewise  measured, 
so  that  a  daily  comparison  may  be  made  between  the  standing  and 
horizontal-walking  temperatures.  These  two  series  of  data,  which 
are  given  in  tables  6a  and  lla,  pages  53  and  67,  are  summarized  in 
table  47,  in  which  it  is  seen  that  the  average  temperature  during  the 
successive  walking-periods  increased  slightly,  even  though  periods  of 
rest  intervened  between  the  periods.  It  likewise  shows  that  the 
variations  in  the  average  standing  temperature  were  relatively  slight 
from  day  to  day  and  that  the  difference  between  the  average  standing 
temperature  and  the  average  temperature  of  the  first  walking-period 
shows  in  several  cases  a  loss.  This  loss  in  temperature  may  have  been 

TABLE  47. — Summary  of  body-temperature  measurements  of  E.  D.  B.  in  horizontal-walking 

experiments  without  food. 


Date. 

Distance 
walked 
per  minute. 

Average  body-temperature  in  successive  periods 
of  horizontal-walking  experiments. 

Average 
body- 
temperature 
during 
standing. 

Increase 
in  body- 
temperature 
due  to 
walking. 

First 
period. 

Second 
period. 

Third 
period. 

Fourth 
period. 

Average. 

1916 
Apr.     3    

meters. 
35.8 
36.6 
51.8 
54.1 
56.6 
60.1 
63.2 
63.6 
66.1 
75.9 
77.7 
77.9 
88.3 
92.3 
97.4 

°C. 

36-86 
36.55 
36.80 
36.86 
36.91 
36.59 
37.03 
37.05 
37.13 
36.90 
37.06 
36.95 
36.95 
36.94 
37.09 

°C. 
37.12 
36.73 
37.02 
37.14 
37.00 
36.78 
37.20 
37.21 
37.17 
37.00 
37.23 
37.09 
37.28 
37.29 
37.46 

°C. 
37.31 
36.84 
37.17 

°C. 

°C. 

37.10 
36.71 
37.00 
37.00 
.  36-96 
36.69 
37.25 
37.22 
37.15 
36.95 
37.22 
37.02 
37.19 
37.22 
37.39 

°C. 
36-68 
36.83 
36.74 
36.67 
36.72 
36.60 
37.22 
37.24 
37.07 
36.88 
36.95 
37.04 
36.95 
36.84 
36.93 

°C. 
0.42 
-.12 
.26 
.33 
.24 
.09 
.03 
-.02 
.08 
.07 
.37 
-.02 
.04 
.38 
.46 

4  

1  

Mar.  31  

29  

20  

Jan.   31    

37.34 
37.28 

37.42 
37.34 

Feb.     1    

Mar.  30  

22  

Apr.     5  

37.38 

10  

12   

37.33 
37.43 
37.62 

11    

13  

Average  .  .  . 

53.1 

36.91 

37.18 

37.30 

37.38 

37.07 

36.89 

.17 

due  to  the  removal  of  the  blanket  from  around  the  subject,  with  a  con- 
sequent increase  in  the  loss  of  heat  from  the  body-surface.  (See  p.  37.) 
It  may  also  have  been  due  to  a  change  in  position  of  the  thermometer  in 
the  rectum,  but  the  care  used  in  inserting  the  thermometer  to  a  definite 
depth  and  the  frequent  balancing  of  the  leads  renders  this  less  likely. 
It  is  unfortunate  that  a  blanket  had  to  be  used,  but  it  was  necessary 
to  protect  the  subject  when  he  was  not  exercising. 


EXPERIMENTS   WITH   HORIZONTAL   WALKING. 


173 


36.80 
36.60 
36.40 

9 

•c. 

36.90 
36.70 
36.50 

A 

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Ml 

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METER 

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87.20 
37.00 

saeo 

9 

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37.64 
57.44 
37.24 
37.04 

36.84 
9 

E 

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2°m.     «         10°°       2 

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5          12g°m.   2°           4 

FIG.  14. — Typical  body-temperature  curves  for  E.  D.  B.  during  periods  of  standing  and  periods 

of  walking  on  a  level  at  various  speeds. 
1,  subject  sitting;  2,  standing;  3,  walking  on  a  level.     Readings  in  experimental  periods  indicated 

by  black  points.     Curve  A,  March  2;  B,  April  4;  C,  April  1;  D,  March  20;  E,  April  12;  F, 

April  13,  1916. 


174  METABOLISM   DURING   WALKING. 

The  relationship  between  the  body-temperature  for  standing  and 
walking  is  also  shown  in  figure  14  by  6  typical  curves  for  different  speeds 
of  walking.  Each  temperature  reading  is  indicated,  those  within  the 
experimental  periods  being  represented  by  black  points  and  those  in 
the  intervals  between  the  experimental  periods  by  small  circles. 
The  changes  to  standing,  walking,  or  sitting  are  shown  by  arrows,  with 
accompanying  index  numbers,  and  the  rate  of  walking  is  given  in 
each  instance.  Curve  A,  for  comparison,  records  sitting  and  stand- 
ing values  only. 

Nearly  every  individual  period  in  each  curve  shows  an  increase  in  the 
temperature  during  the  period  with  both  standing  and  walking.  There 
is  usually  a  disturbance  in  the  temperature  at  the  points  indicated  by 
arrows  when  the  subject  changed  his  position,  which  is  possibly  due  to  a 
change  in  position  of  the  thermometer.  The  curve  of  April  4  (B)  is  in- 
serted especially  to  show  the  marked  variation  in  temperature  which  was 
experienced  when  the  subject  stood  (2)  at  10h  30™  a.  m.  before  the  third 
period  and  again  when  he  began  walking  (3)  at  llh  6m  a.  m.  before  the 
fourth  period.  It  is  possible  that  the  depression  in  temperature  before 
the  fourth  period  may  have  been  due  to  removal  of  the  blanket,  though 
no  note  regarding  it  appears  in  the  records.  In  both  these  instances 
the  temperature  fell  for  at  least  10  minutes,  after  which  it  became 
settled  and  subsequently  rose  as  usual.  This  displacement  of  the 
temperature  level  results  in  an  average  walking  temperature  which  is 
less  than  the  average  standing  temperature,  but  it  is  seen  that  the 
increase  during  the  walking-periods  was  of  about  the  same  order  as  on 
the  other  days. 

The  increase  in  temperature  with  the  transition  from  standing  to 
walking  does  not  manifest  itself  immediately  for  the  moderate  speeds 
(see  curves  B,  C,  and  D  for  April  4,  April  1,  and  March  20),  there 
being  apparently  a  lag  of  from  6  to  10  minutes  before  the  rise  appears. 
This  lag  is,  however,  somewhat  shortened  in  curves  E  and  F  (April  12 
and  13),  with  speeds  of  88  and  97  meters.  These  latter  curves  show  a 
much  more  rapid  rise  in  temperature  in  each  period,  with  a  tendency 
to  reach  a  maximum,  particularly  in  curve  E.  The  fact  that  the 
blanket  was  removed  at  the  time  that  the  walking  began  is  undoubtedly 
a  factor  here  in  preventing  as  quick  a  response  as  there  would  have  been 
had  the  subject  stood  and  walked  under  exactly  the  same  conditions  of 
clothing.  The  increase  in  temperature  is  almost  always  larger  for  the 
first  walking-periods  than  for  the  subsequent  periods,  showing  that 
the  difference  between  the  rate  of  heat-production  and  radiation  was 
becoming  constantly  less  and  that  a  more  or  less  constant  temperature 
would  have  been  attained  had  the  period  been  sufficiently  prolonged. 

The  effect  of  speed  of  walking  upon  the  temperature  curves  is  not 
marked,  except  at  the  higher  rates.  The  general  character  of  the 
curves  in  figure  14  and  others  not  presented  indicate  but  little  difference 


EXPERIMENTS   WITH   HORIZONTAL   WALKING.  175 

at  the  different  speeds.  Apparently  the  exercise  of  walking  at  the 
normal  speeds  used  for  the  most  part  in  this  research  was  not  sufficient 
to  produce  any  marked  changes  in  body-temperature.  Referring  again 
to  table  47,  in  which  it  has  been  necessary  to  compare  only  the  average 
temperatures,  it  is  seen  that  although  the  highest  absolute  temperature 
and  largest  increases  over  the  standing  values  are  with  the  highest 
speeds,  the  lowest  speed  also  has  a  high  average  temperature  as  well  as 
large  increase,  and  that  the  increases  over  the  standing  temperatures 
are  irregular.  The  average  walking  temperature  would  depend  upon 
the  duration  of  walking  as  well  as  upon  the  speed.  Consequently,  no 
definite  statement  as  to  the  influence  of  speed  can  be  made  other  than 
that,  in  the  intermittent  periods  here  conducted,  the  maximum  in- 
crease for  any  speed  below  100  meters  per  minute  did  not  exceed 
0.5°  C.,  and  that  for  moderate  speeds  the  temperature  increase  would 
probably  be  not  far  from  0.25°  C. 

BLOOD-PRESSURE  DURING  HORIZONTAL  WALKING. 

The  increase  in  the  supply  of  oxygen  to  the  tissues  with  increased 
demand  due  to  exercise  is  dependent  upon  a  chain  of  processes.  The 
increase  in  pulmonary  ventilation  and  pulse-rate,  the  change  in  the  dis- 
tribution of  the  blood-flow  to  those  muscles  more  in  need  of  oxygen,  and 
the  general  increase  in  the  blood-flow  itself,  all  contribute  to  the  imme- 
diate supply  of  oxygen.  The  increase  in  the  blood-flow  is  one  of  the 
largest,  if  not  the  largest,  factor  in  maintaining  this  addition  to  the 
oxygen-supply,  and  Krogh  and  Lindhard1  have  shown  that  during 
work  the  blood-flow  may  be  eight  times  that  during  rest.  This  increase 
in  blood-flow  is,  at  least  above  certain  limits,  accompanied  by  an  in- 
crease in  blood-pressure.  It  thus  becomes  of  interest  to  record  the  blood- 
pressure  during  periods  of  exercise,  and  this  was  done  with  E.  D.  B.  for 
both  the  standing  and  walking  experiments  overaperiod  of  several  weeks. 
During  this  time  there  were  13  days  on  which  records  of  the  blood-pres- 
sure were  made  for  both  standing  and  horizontal-walking  periods.  These 
horizontal-walking  values  are  recorded  in  table  1  la  (p.  67)  .  It  should  be 
recalled  that  they  were  taken  just  prior  to  and  immediately  following 
the  periods  of  walking  proper,  as  it  was  not  possible  to  read  the  pres- 
sure during  the  act  of  walking.  (See  p.  37.)  Cotton,  Rapport,  and 
Lewis2  have  recently  shown  that  the  blood-pressure  immediately  on 
the  cessation  of  exercise  indicates  little  or  no  increase  above  the  rest- 
ing value,  but  within  10  seconds  it  begins  to  increase  and  continues  to 
rise  for  a  period  of  30  to  60  seconds,  after  which  it  again  tends  to  fall  to 
normal  value.  While  it  is  possible  that  the  readings  as  reported  by  us 
may  not  have  occurred  at  the  point  of  maximum  pressure  following 
walking,  it  is  quite  certain  that  the  readings  were  close  to  it  and  beyond 


and  Lindhard,  Skand.  Arch.  f.  Physiol.,  1912,  27,  p.  100. 
'Cotton,  Rapport,  and  Lewis,  Heart,  1917,  6,  p.  269. 


176 


METABOLISM    DURING   WALKING. 


the  point  of  minimum  value  at  10  seconds.  Although  the  readings  can 
not  be  said  to  be  the  blood-pressures  during  horizontal  walking,  it 
is  believed  that  they  approach  closely  to  them,  and  as  the  conditions 
under  which  the  readings  were  made  were  alike,  the  results  are  com- 
parable. 

Disregarding  the  fact  that  there  was  some  variation  in  the  speed  of 
walking  for  the  periods  on  the  same  day,  it  is  seen  in  table  lla  that  the 
blood-pressure  shows  but  little  tendency  to  change  from  period  to 
period  on  the  same  day,  the  difference  being  ±2  mm.,  with  an  extreme 
of  4  mm.  on  two  occasions. 

For  a  comparison  between  the  average  standing  and  the  average 
walking  blood-pressures  on  the  same  date,  a  summary  is  presented  in 
table  48.  The  blood-pressure  for  the  first  walking-periods  is  here  seen 
to  be  5  to  16  mm.  higher  than  the  average  standing  values  for  the  same 
day.  The  average  increase  is  9  mm. 

TABLE  48. — Summary  of  bloods-pressure  records  for  E.  D.  B.  in  horizontal-walking  experi- 
ments without  food. 


Date. 

Distance 
walked 
per 
minute. 

Average    blood-pressure    in    successive 
periods     of     horizontal-walking     ex- 
periments. 

Average 
blood- 
pressure 
during 
standing. 

Increase 
in  blood- 
pressure 
due  to 
walking. 

First 
period. 

Second 
period. 

Third 
period. 

Average. 

1916. 
Apr.      3  

meters. 
35.8 
36.6 
51.8 
54.1 
56.6 
60.1 
66.1 
75.9 
77.7 
77.9 
88.3 
92.3 
97.4 

mm. 
124 
117 
124 
124 
124 
122 
119 
122 
123 
129 
130 
130 
131 

mm. 
123 
118 
125 
127 
125 
123 
117 
118 
127 
129 
129 
129 
131 

mm. 
121 
118 
123 

mm. 
123 
118 
124 
126 
'     125 
123 
118 
120 
125 
129 
130 
129 
131 

mm. 
116 
113 
115 
120 
109 
114 
113 
110 
118 
121 
118 
118 
117 

mm. 
7 
5 
9 
6 
16 
9 
5 
10 
7 
8 
12 
11 
14 

4  

1  

Mar.  31  

29  

20  

30  

22  

Apr.      5  

125 

10  

12  

130 
129 
131 

11  

13  

Average  .... 

67.0 

125 

125 

125 

125 

116 

9 

The  degree  of  increase  over  the  standing  does  not  show  an  evident 
connection  with  the  speed,  nor  does  the  speed  of  walking  show  a  uni- 
form effect  upon  the  absolute  blood-pressure  readings  until  the  rate  of 
88.3  meters  per  minute  is  reached.  At  this  point  the  blood-pressure 
is  noticeably  higher  than  for  the  more  moderate  speeds.  The  average 
blood-pressure  for  the  horizontal-walking  experiments  on  the  days 
when  the  speed  was  75.9  meters  per  minute  or  below  was  122  mm.,  and 
ranged  from  118  to  126  mm.  Above  75.9  meters  per  minute  it  was 
129  mm.,  ranging  from  125  to  131  mm. 


PHYSIOLOGY   OF   MOUTH-BREATHING   APPLIANCES.  177 

The  effect  of  horizontal  walking  upon  the  blood-pressure  is  there- 
fore not  large,  even  at  the  highest  speeds  here  reported,  as  compared 
with  the  increases  in  blood-pressures  known  to  occur  with  other  forms 
of  work,  such  as  those  found  in  exercise  with  dumb-bells  by  Cotton, 
Rapport,  and  Lewis.1  There  is,  however,  a  point  above  80  meters  per 
minute  at  which  the  effect  upon  the  blood-pressure  of  the  speed  of 
walking  may  be  clearly  noted. 

EXPERIMENTS  WITH  GRADE  WALKING. 

As  explained  in  the  section  on  methods  (p.  29),  the  treadmill  was 
constructed  with  two  long  screw  members  attached  to  the  head,  by 
means  of  which  the  front  of  the  treadmill  could  be  raised  so  as  to  give 
angles  of  elevation  as  desired  up  to  approximately  45°.  Aside  from 
the  fact  that  under  these  conditions  the  subject  walked  on  a  pre- 
determined incline,  the  details  of  the  grade-walking  experiments  were 
in  no  respect  different  from  those  with  horizontal  walking.  As  the 
degree  of  elevation  increased,  less  power  was  needed  to  drive  the  tread- 
mill, and  at  the  highest  grades  the  weight  of  the  subject  alone  would 
have  been  sufficient  to  cause  the  speed  to  increase  continuously.  To 
control  this  and  thus  secure  uniformity  in  speed,  an  adjustable  brake 
was  placed  on  the  shaft  of  the  motor.  (See  p.  29  and  fig.  1,  p.  19.) 
This  tendency  to  an  increase  in  speed  during  the  experiment  was  a 
frequent  source  of  trouble,  and  careful  attention  was  required  to  pre- 
vent any  gradual  alteration  in  speed  from  unexpectedly  developing. 

The  results  of  the  measurements  in  the  grade-walking  experiments 
are  given  hi  detail  in  tables  13  to  16a  (pp.  69  to  89),  in  which  the  values 
are  chronologically  arranged  for  all  of  the  experimental  periods  with 
every  subject.  Before  discussing  the  results  of  these  experiments,  a 
consideration  of  the  method  used  for  studying  the  respiratory  exchange 
is  desirable,  more  especially  the  use  of  the  mouthpiece  under  the  special 
conditions  of  grade  walking. 

PHYSIOLOGY  or  MOUTH-BREATHING  APPLIANCES. 

While  the  mouthpiece  in  its  various  forms  has  been  extensively  used 
for  respiration  experiments  with  the  subject  lying  or  standing  or  walk- 
ing, there  has  been  much  criticism  by  investigators  as  to  the  physio- 
logical effects  of  using  such  an  appliance.  Some  go  so  far  as  to  state 
that  it  is  physiologically  impossible  for  a  man  to  breathe  normally 
through  a  mouthpiece.  This  extreme  opinion  is  held  by  only  a  few 
workers  on  the  respiratory  exchange.  With  walking  experiments, 
however,  the  question  might  fairly  be  raised  whether  the  use  of  the 
mouthpiece  would  affect  the  results  obtained,  more  especially  during 
the  severe  exercise  of  grade  walking,  when  the  oxygen  consumption 
would  necessarily  be  very  considerable  and  the  pulmonary  ventila- 

,  Rapport,  and  Lewis,  Heart,  1917,  6,  p.  269. 


178  METABOLISM   DURING   WALKING. 

tion  especially  large.  Is  the  resistance,  for  example,  too  great?  Of 
special  interest  is  the  fact  that  much  of  this  report  deals  with  the 
physiology  of  respiration  during  the  period  of  transition  from  standing 
to  walking,  and  the  reverse  from  walking  to  standing.  If  breathing 
through  a  mouthpiece  is  abnormal,  the  value  of  these  studies  of  transi- 
tion would  be  lessened. 

In  the  ordinary  technique  the  mouthpiece  is  usually  inserted  about 
two  minutes  before  the  actual  experiment  begins.  To  test  the  question 
as  to  whether  this  preliminary  period  of  breathing  through  the  mouth- 
piece was  sufficiently  long  for  the  subject  to  adjust  himself  to  the  new 
conditions,  a  number  of  experiments  were  carried  out  in  which  the 
mouthpiece  was  inserted  15  or  more  minutes  before  the  actual  beginning 
of  the  experiment,  and  a  comparison  series  of  experiments  was  made 
in  which  the  mouthpiece  was  inserted  almost  immediately,  i.  e.,  a  few 
seconds  before  the  period  began.  These  experiments  were  all  with 
E.  D.  B.  between  March  2  and  8,  1916,  inclusive.  On  two  of  the  days 
the  subject  stood;  on  four  of  the  days  he  walked  on  a  30  per  cent  incline 
at  a  rate  of  approximately  50  meters  per  minute.  The  standing  or 
walking  was  continuous  on  every  day  throughout  each  set  of  two  com- 
parison periods,  and  at  the  end  the  subject  sat  down  and  rested.  In 
the  first  period  in  each  pair  the  subject  breathed  through  the  mouth- 
piece on  an  average  of  15  minutes  before  the  period  began.  The  actual 
period  for  the  measurement  of  the  metabolism  varied  from  7  minutes 
and  24  seconds  to  10  minutes  and  52  seconds,  averaging  not  far  from 
9  minutes.  There  was  then  an  interval  which  was  usually  10  to  12 
minutes  long.  On  March  4  the  first  interval  was  20  minutes  and  on 
March  7  the  interval,  owing  to  some  trouble  with  the  apparatus,  was 
50  minutes.  On  both  these  days  walking  experiments  were  made,  and 
the  subject  walked  continuously  even  in  these  intervals. 

In  the  second  period  hi  the  comparison  the  mouthpiece  was  not  in- 
serted until  just  before  the  beginning  of  the  test,  so  that  usually  the 
period  began  on  the  second  respiration,  with  an  interval  between  the 
insertion  of  the  mouthpiece  and  the  beginning  of  the  metabolism 
measurements  of  never  more  than  15  seconds.  Since  this  procedure 
was  carried  out  in  both  the  standing  and  walking  comparisons,  it 
would  seem  as  if  the  influence  of  mouthpiece  breathing  upon  the  metab- 
olism and  physiological  factors  should  be  demonstrated  by  such  a 
series  of  tests. 

EFFECT  OF  MOUTHPIECE  BREATHING  UPON  METABOLISM. 

Although  the  data  for  these  comparison  tests  are  incorporated  in  the 
statistical  tables  6  and  16,  they  are  also  summarized  here  in  table  49. 
In  the  first  test,  namely,  March  2, 1916,  the  influence  on  the  metabolism 
of  the  time  of  insertion  of  the  mouthpiece  was  studied  only  with  the 
subject  standing,  and  three  comparisons  were  made.  On  March  3  the 


PHYSIOLOGY   OF   MOUTH-BREATHING   APPLIANCES. 


179 


TABLE  49. — Respiratory  exchange  of  E.  D.  B.  in  experiments  without  food  for  studying  effect 
of  long  and  short  duration  of  preliminary  mouthpiece  breathing.1    ( Values  per  minute.) 


Date,  No.  of 
comparison,  and 
conditions  of 
experiment. 

Work  due  to 
grade-lift.2 

Carbon  dioxide. 

Oxygen. 

Respiratory 
quotient. 

After  15 
minutes 
prelimi- 
nary 
mouth- 
piece 
breath- 
ing. 

After  15 
seconds 
prelimi- 
nary 
mouth- 
piece 
breath- 
ing. 

After  15 
minutes 
prelimi- 
nary 
mouth- 
piece 
breath- 
ing. 

After  15 
seconds 
prelimi- 
nary 
mouth- 
piece 
breath- 
ing. 

After  15 
minutes 
prelimi- 
nary 
mouth- 
piece 
breath- 
ing. 

After  15 
seconds 
prelimi- 
nary 
mouth- 
piece 
breath- 
ing. 

After  15 
min  utes 
prelimi- 
nary 
mouth- 
piece 
breath- 
ing. 

After  15 
seconds 
prelimi- 
nary 
mouth- 
piece 
breath- 
ing. 

Standing. 
Mar.  2: 
First  

kg.  m.  . 

kg.  m. 

c.  c. 
202 
198 
185 

c.  c. 
192 
187 
192 

c.  c. 
236 
244 

(J) 

c.  c. 
239 
229 
(243) 

0.86 
.81 

(') 

0.81 
.82 
.79 

Second  

Third  

Average  .  .  . 

195 

190 

240 

234 

.83 

.81 

Mar.  3: 
First  

186 
197 
185 

194 
191 
186 

240 
241 
233 

244 
246 
241 

.78 
.82 
.79 

.80 

.78 
.77 

Second  

Third  

Average.  .  . 

189 

190 

238 

243 

.80 

.79 

Grade  walking.4 
Mar.  4  : 
First  

898.5 
863.8 

889.4 
898.5 

1,621 
1,552 

1,624 
1,625 

1,764 
1,751 

1,829 
1,914 

.92 
.89 

.89 
.86 

Second  

Average  .  .  . 

Mar.  6: 
First  

881.2 

894.0 

1,587 

1,625 

1,758 

1,872 

.91 

.87 

933.6 
959.2 

953.7 
968.3 

1,763 
1,800 

1,783 
1,795 

1,923 
2,044 

2,013 
2,015 

.92 

.88 

.80 
.89 

Second   

Average  .  .  . 

Mar.  7: 
First  

946.4 

961.0 

1,782 

1,789 

1,984 

2,014 

.90 

.89 

925.7 

927.5 

1,774 

1,682 

1,909 

1,942 

.93 

.87 

Mar.  8: 
First     

924.7 
926.5 
930.1 

924.7 
944.5 
933.7 

1,761 
1,807 
1,769 

1,735 
1,766 
1,723 

1,891 
1,961 
2,011 

1,942 
2,073 
2,043 

.93 
.92 
.88 

.89 
.85 
.84 

Second  

Third  

Average  .  .  . 

927.1 

934.3 

1,779 

1,741 

1,954 

2,019 

.91 

.86 

JThe  subject  stood  continuously  or  walked  continuously  in  each  comparison,  i.  e.,  also  in  the 
interval  between  the  two  tests.  Between  the  comparisons  he  sat  down  and  rested  for  approxi- 
mately 30  to  40  minutes.  The  time  given  for  the  preliminary  mouthpiece  breathing  is  approxi- 
mate. 

2See  table  55,  column/,  p.  209. 

'Measurement  of  oxygen  could  not  be  obtained  in  this  period. 

4In  the  grade-walking  experiments,  the  grade  was  30  p.  ct.  and  the  speed  averaged  49  meters 
on  March  4,  51  meters  on  March  6,  and  52  meters  on  March  7  and  8. 


180  METABOLISM   DURING   WALKING. 

series  was  duplicated  under  the  same  conditions.  Considering  average 
values  only,  it  can  be  seen  that  the  carbon  dioxide  on  the  first  day  was 
slightly  larger  when  the  mouthpiece  was  inserted  15  minutes  before  the 
test,  but  on  the  second  day  it  was  practically  the  same  with  both  periods 
of  preliminary  breathing.  The  oxygen  consumption  was  somewhat 
higher  on  the  first  day  and  correspondingly  lower  on  the  second  day 
with  the  long  preliminary  breathing.  The  respiratory  quotient  was 
slightly  higher  in  both  series  of  tests  with  the  longer  preliminary 
breathing.  The  evidence  as  a  whole  can  not  be  said,  however,  to 
indicate  that  with  this  subject  standing  there  is  an  appreciable  differ- 
ence in  the  effect  upon  the  measured  metabolism  as  to  whether  the 
mouthpiece  is  inserted  15  minutes  before  the  period  begins  or  imme- 
diately before. 

On  four  days  walking  experiments  were  made,  and  while  there  was 
every  effort  to  secure  exactly  the  same  rate  of  walking,  unfortunately 
this  could  not  be  maintained.  Slight  differences  in  the  total  amount  of 
work  performed  accordingly  appear.  While  the  rate  of  walking  was 
approximately  50  meters  per  minute,  a  little  less  than  2  miles  an  hour, 
it  actually  varied  in  the  different  periods  on  these  days  from  47.2  to 
53.0  meters  per  minute.  Usually  the  rate  of  walking  was  slightly 
greater  with  the  second  test  in  the  comparison,  namely,  that  with  the 
short  preliminary  breathing,  the  difference  averaging  not  far  from 
1  per  cent.  These  differences  are  important  to  take  into  consideration 
in  the  analysis  of  the  results. 

Of  the  two  factors,  carbon  dioxide  and  oxygen,  one  would  naturally 
expect  that  an  abnormality  in  respiration  due  to  the  mouthpiece  would 
produce  more  immediate  fluctuations  in  the  amount  of  carbon  dioxide 
exhaled.  This  may  be  owing  to  a  local  "pumping-out"  effect,  and 
consequently  it  is  not  surprising  that  the  values  for  carbon  dioxide  do 
not  show  regularity.  On  the  first  two  days  with  grade  walking  these 
values  are  somewhat  higher,  and  on  the  last  two  days  measurably  lower 
with  the  short  preliminary  breathing  period.  Since,  as  stated  above, 
when  there  was  a  difference  in  the  rate  of  walking,  it  was  almost 
invariably  more  rapid  in  the  second  test  of  the  comparison,  it  can  be 
seen  that  there  is  no  relationship  between  the  carbon  dioxide  and  the 
slightly  higher  rate  of  walking,  nor  indeed  any  relationship  with  the  use 
of  the  mouthpiece,  and  the  differences  in  amounts  simply  illustrate  the 
variability  in  the  carbon-dioxide  excretion  that  one  may  expect  to 
find  under  the  conditions  of  a  test  Iik9  this. 

A  truer  measure  of  the  metabolism  is  the  oxygen  consumption,  and 
we  find  here  that  on  all  four  days  the  oxygen  consumption  was  slightly 
higher  in  the  period  with  the  short  preliminary  breathing.  This  is 
almost  always  in  full  accord  with  the  slight  differences  in  the  rate  of 
walking,  and  can  therefore  be  readily  explained  by  an  increase  in  the 
oxygen  consumption  necessitated  by  an  increase  in  the  rate  of  walking. 


PHYSIOLOGY   OF   MOUTH-BREATHING   APPLIANCES.  181 

That  it  is  not  wholly  explained  by  this  is  shown  by  the  fact  that  the 
average  increase  in  the  rate  of  walking  with  the  short  preliminary 
breathing  period  is  only  about  1  per  cent  as  compared  with  the  actual 
increment  of  2  per  cent  in  the  oxygen  consumption.  The  evidence  is 
therefore  to  the  effect  that  with  but  15  seconds  of  preliminary  mouth- 
piece breathing,  a  slightly  greater  oxygen  consumption  is  required 
during  the  experimental  period  than  with  15  minutes  of  preliminary 
breathing  through  the  mouthpiece. 

The  respiratory  quotient  on  the  four  days  is  invariably  lower  with 
the  short  period  of  preliminary  breathing.  At  tunes  the  difference  is 
very  considerable,  even  as  large  as  0.06.  It  is  therefore  clear  that  the 
mouthpiece  breathing  is  not  ideally  adapted  for  an  analysis  of  the 
character  of  the  combustion  when  heavy  work  is  being  performed. 
A  large  number  of  experiments  have  been  made  in  the  Nutrition  Labo- 
ratory on  the  comparison  of  various  types  of  respiration  apparatus, 
using  mouthpieces,  nosepieces,  and  masks,  and  these  show  that  for 
periods  of  rest  no  appreciable  difference  exists  between  the  various 
types  employed.1  The  true  respiratory  quotient  obtained  in  these 
walking  experiments  is  difficult  to  valuate.  A  priori,  one  could  take 
the  ground  that  the  longer  the  mouthpiece  was  inserted  in  the  mouth, 
the  more  normal  the  respiration  would  be.  But  in  any  event  the 
percentage  error  is  small,  probably  not  over  2  per  cent,  and  the  measure- 
ments of  the  metabolism  under  conditions  of  great  physical  activity, 
such  as  obtained  in  many  of  the  experiments  reported  in  this  book, 
can  hardly  be  much,  if  any,  inside  of  this  limit  of  accuracy.  The 
natural  conclusion  is,  therefore,  that  although  practically  all  of  the 
experiments  were  made  with  a  short  period  of  preliminary  mouthpiece 
breathing,  rather  than  a  15-minute  period  of  preliminary  breathing, 
and  these  tests  indicate  that  the  metabolism  is  thereby  slightly  increased 
if  measured  by  the  oxygen  consumption,  yet  it  does  not  seem  advisable 
to  attempt  a  correction  of  the  results  for  the  small  differences  shown  in 
this  series  of  tests. 

As  previously  stated,  in  actual  experiments  the  mouthpiece  is  usually 
inserted  about  2  minutes  before  the  observations  of  the  metabolism 
begin.  This  preliminary  period  is  measurably  greater  than  the  short 
period  in  the  series  of  comparison  tests,  but  much  shorter  than  the 
15-minute  periods.  Doubtless  the  error  due  to  the  insertion  of  the 
mouthpiece  is  not  distributed  in  a  straight  line,  and  it  is  more  than 
reasonable  to  suppose  that  at  the  end  of  2  minutes  the  oxygen  con- 
sumption is  more  nearly  in  accord  with  that  obtained  with  the  longer 
period  of  preliminary  respiration  than  with  that  with  the  very  short 
period. 

Carpenter,  Carnegie  Inst.  Wash.  Pub.  No.  216,  1915.     Also,  Hendry,  Carpenter,  and  Emmes, 
Boston  Med.  and  Surg.  Journ.,  1919,  181,  pp.  285,  334,  and  368. 


182  METABOLISM   DURING   WALKING. 

EFFECT  OF  MOUTHPIECE  BREATHING  UPON  RESPIRATION-RATE,  PULMONARY  VENTILATION, 
AND  RATE  OF  OXYGEN  CONSUMPTION. 

The  effect  upon  the  respiration-rate  and  the  pulmonary  ventilation 
of  long-continued  preliminary  breathing  through  the  mouthpiece  was 
also  studied  in  these  experiments,  for  it  was  conceivable  that  the  mouth- 
piece and  nose-clip  might  cause  a  change  in  the  ventilation  which  would 
result  hi  a  pumping-out  of  carbon  dioxide  and  a  consequent  change  in 
the  respiratory  quotient  and  the  computed  heat.  As  previously 
stated,  hi  ordinary  experimenting  it  has  been  the  practice  to  insert  the 
mouthpiece  2  or  more  minutes  before  the  beginning  of  the  period.  If 
there  were  any  alteration  in  the  respiration-rate  and  volume  of  venti- 
lation under  these  conditions,  it  ought  to  be  apparent  in  experiments 
made  with  such  wide  variations  in  the  length  of  preliminary  breathing 
as  comparison  periods  of  15  seconds  and  15  minutes  would  give.  If 
this  variation  in  conditions  resulted  in  no  material  difference,  it  is  safe 
to  say  that  the  usual  2-minute  period  of  preliminary  breathing  through 
the  mouthpiece  was  sufficient  to  insure  uniformity. 

The  respiration-rate  and  pulmonary  ventilation  were  determined  in 
1-minute  and  )^-immite  intervals  during  the  first  5  to  7  minutes  of  the 
period  by  counting  the  respirations  and  measuring  their  excursion  on 
the  kymograph,  the  time-intervals  being  marked  in  minutes  by  means 
of  a  signal  magnet  in  contact  with  a  clock.  The  ventilation  as  thus 
measured  is  the  apparent  ventilation,  and  the  data  have  not  been  cor- 
rected for  temperature  changes. 

At  the  time  that  these  measurements  of  the  ventilation  were  made, 
advantage  was  taken  of  the  opportunity  to  measure  the  rate  of  the 
oxygen  consumption  during  the  first  few  minutes  of  the  period.  This 
was  done  by  the  use  of  the  double  spirometer  (see  fig.  2,  p.  22),  and  the 
measurement  of  the  kymograph  record.  During  the  regular  experi- 
ments it  was  the  practice  to  admit  the  oxygen  at  such  a  rate  as  to 
equalize  the  consumption,  but  in  determining  the  rate  in  the  mouth- 
piece comparison  experiments,  no  oxygen  was  admitted  until  the 
spirometer-bell  had  reached  a  low  level.  The  main  spirometer  was 
then  refilled  from  the  duplicate  spirometer  by  the  method  described 
on  page  21.  Under  these  conditions,  instead  of  a  gradual  alteration 
in  the  relative  positions  of  the  kymograph  tracings  as  a  result  of 
the  contractions  in  the  volume  of  the  ventilating  circuit,  the  kymo- 
graph record  showed  a  slight  rise  with  each  respiration  and  a  sud- 
den fall  when  new  oxygen  was  finally  admitted  from  the  duplicate 
spirometer.  By  measuring  the  rise  in  the  kymograph  record  due  to 
the  fall  of  the  spirometer-bell  in  a  specified  period  of  time,  the  rate  of 
oxygen  consumption  could  be  estimated  for  succeeding  fractions  of  a 
minute. 

There  is  a  valid  criticism  against  this  method  of  measurement,  for  it 
assumes  that  the  subject  exhales  to  the  same  point  of  deflation  of  the 


PHYSIOLOGY   OF   MOUTH-BREATHING   APPLIANCES. 


183 


lungs  each  time  and  that  the  residual  volume  in  the  lungs  and  the 
temperature  conditions  remain  constant.  Any  alteration  in  the  resid- 
ual volume  would  alter  the  base  of  the  respiration  tracings  on  the 
kymograph.  This,  of  course,  does  occur  occasionally  in  a  deep  inhala- 
tion, but  the  low  points  of  the  tracings  which  mark  the  limits  of  expira- 
tion are  remarkably  uniform  after  the  first  few  respirations  of  the  period, 
and  the  rate  at  which  these  points  rise  give  a  very  fair  index  of  the  rate 
of  oxygen  consumption.  The  method,  however,  is  intended  merely 
as  an  approximate  comparison,  for  the  volumes  thus  read  are  apparent 
volumes  and,  like  those  for  the  pulmonary  ventilation,  are  uncorrected 
for  temperature  changes. 

The  lower  record  (A)  in  figure  15  is  the  reproduction  of  a  kymograph 
tracing  when  the  subject  was  standing  and  shows  the  rise  in  the  curve 
as  the  oxygen  was  absorbed  from  the  ventilating  circuit,  without  re- 
newal. The  upper  record  (B)  in  the  same  figure  was  obtained  with 
the  subject  walking,  and  indicates  the  points  at  which  the  main  spirom- 
eter  was  refilled  from  the  duplicate  spirometer. 


-I — r 


-i — i — i- 


-f — 
-I) — Ih 


FIG.  15. — Reproduction  of  kymograph  records  in   mouthpiece  experiments, 

with  intermittent  renewal  of  oxygen. 
A,  subject  standing  without  introduction  of  oxygen.     B,  subject  walking  on 

a  30  per  cent  grade,  50  meters  per  minute;  intermittent  renewal  of  oxygen. 

Time  and  pulmonary  ventilation  indicated  by  the  horizontal  tracings. 


184  METABOLISM   DURING   WALKING. 

EFFECT  WITH   SUBJECT   STANDING. 

In  table  50  the  data  for  the  respiration  and  ventilation  rates  ob- 
tained with  the  subject  standing  are  given  for  E.  D.  B.  for  March  2 
and  3, 1916.  In  the  first  test  in  each  comparison  the  subject  had  been 
standing  with  the  mouthpiece  inserted  for  at  least  15  minutes  previous 
to  the  beginning  of  the  measurements.  In  this  test  the  values  were 
measured  in  minute  intervals.  In  the  second  test  of  each  comparison 
the  mouthpiece  was  inserted  but  a  few  seconds  before  the  measurements 
began.  The  measurements  were  made  in  quarter  minutes  and  the  per 
minute  rate  calculated  from  the  results.  These  quarter-minute  rates 
are  also  averaged  for  comparison  with  the  measurement  for  the  cor- 
responding full  minute  in  the  preceding  test,  when  the  mouthpiece  was 
inserted  15  minutes. 

Three  comparisons  were  obtained  with  the  subject  standing  on  both 
March  2  and  3,  with  intervals  of  rest  of  30  minutes  or  more  between 
the  first  and  second  and  the  second  and  third  comparisons.  The 
respiration-rate  in  the  periods  when  the  mouthpiece  had  been  used  for 
approximately  15  minutes  does  not,  on  the  whole,  appear  to  be  different 
from  the  rate  when  the  mouthpiece  was  inserted  immediately  before 
the  experiment.  There  seems  to  be  a  slight  tendency  for  the  respira- 
tion-rate to  increase  with  the  time,  but  this  is  as  apparent  with  the  long 
preliminary  breathing  as  with  the  short. 

In  most  cases,  when  the  pulmonary  ventilation  was  calculated  on  the 
quarter-minute  basis,  a  slightly  larger  ventilation  was  found  for  the 
first  quarter-minute  during  the  periods  when  the  mouthpiece  had  been 
but  briefly  inserted.  There  are,  however,  several  exceptions  to  this. 
No  greater  variation  was  found  under  one  condition  than  under  the 
other,  if  we  take  the  per  minute  averages  for"  comparison.  With  the 
exception  of  a  slight  disturbance  for  the  first  one-quarter  minute,  it 
appears  that  the  ventilation  was  as  constant  under  one  condition  as 
under  the  other,  and  that  both  the  respiration  and  ventilation  with  the 
subject  standing  were  unaffected  by  the  presence  of  the  mouthpiece 
during  a  short  or  a  long  preliminary  breathing. 

The  oxygen  consumption  per  minute  for  the  first  7  or  8  minutes  of 
each  period  was  computed  as  outlined  on  page  182.  Considerable  varia- 
tions actually  occur  hi  single  minutes,  the  range  being,  with  the  subject 
standing,  from  186  to  418  c.  c.  per  minute.  Little,  if  any,  regularity 
can  be  observed  on  any  day,  although  it  is  worthy  of  note  that  both 
the  extreme  values  occurred  in  the  first  minute.  The  inherent  errors 
hi  the  method  of  measurement  outlined  above  make  its  use  questionable 
when  such  small  per  minute  amounts  of  oxygen  were  obtained,  and 
hence  we  do  not  tabulate  them. 

EFFECT  DURING   GRADE  WALKING. 

On  March  4,  6,  7,  and  8,  the  usual  grade-walking  experiments  were 
varied  to  the  extent  that  in  each  alternate  period  the  subject  breathed 


PHYSIOLOGY   OF   MOUTH-BREATHING   APPLIANCES. 


185 


TABLE  50. — Respiration-rate  and  rate  of  pulmonary  ventilation  (unreduced)  in  experiments  without  food,  for  studying 
effect  of  long  and  short  duration  of  preliminary  mouthpiece  breathing.  Subject,  E.  D.  B.,  standing.  (Values 
per  minute.) 


Date  and 
interval 
measured. 

First  comparison. 

Second  comparison. 

Third  comparison. 

After  15 
minutes 
preliminary 
mouthpiece 
breathing. 

After  15 
seconds 
preliminary 
mouthpiece 
breathing. 

After  15 
minutes 
preliminary 
mouthpiece 
breathing. 

After  15 
seconds 
preliminary 
mouthpiece 
breathing. 

After  15 
minutes 
preliminary 
mouthpiece 
breathing. 

After  15 
seconds 
preliminary 
mouthpiece 
breathing. 

Respi- 
ration- 
rate 
(full 
min- 
utes) . 

Rate 
of  pul- 
monary 
venti- 
lation 
unre- 
duced 
(full 
min- 
utes). 

Respi- 
ration- 
rate 
(X 
min.). 

Rate 
of  pul- 
monary 
venti- 
lation, 
unre- 
duced 

(X 

min.). 

Respi- 
ration- 
rate 
(full 
min- 
utes) . 

Rate 
of  pul- 
monary 
venti- 
lation 
unre- 
duced 
(full 
min- 
utes). 

Respi- 
ration- 
rate 

(X 

min.). 

Rate 
of  pul- 
monary 
venti- 
lation, 
unre- 
duced 
(K 
min.). 

Respi- 
ration- 
rate 
(full 
min- 
utes) . 

Rate 
of  pul- 
monary 
venti- 
lation 
unre- 
duced 
(full 
min- 
utes). 

Respi- 
ration- 
rate 

(Y* 

min.). 

Rate 
of  pul- 
monary 
venti- 
lation, 
unre- 
duced 

(X 

min.). 

1916. 
Mar.  2: 

1st  min  
2d  min  

15.1 
14.6 
15.5 
15.2 

16.8 
16.5 

liters. 
9.5 

9.9 
10.3 
10.4 
11.1 

15.2 
14.3 
15.0 
15.5 

liters. 
11.2 
10.2 
10.3 
9.0 

15.9 
13.8 
13.9 
16.3 
15.1 

liters. 
10.6 

9.3 
9.0 
10.6 
10.1 

12.9 
13.1 
12.9 
16.2 

liters. 
9.2 
9.3 
9.0 
8.5 

16.0 
15.0 
15.7 
16.5 
16.6 

liters. 
9.6 

9.6 
10.4 
10.2 
10.6 

16.6 
15.5 
15.2 
15.2 

liters. 
11.6 
11.1 
9.6 
10.5 

15.0 

10.2 

13.8 

9.0 

15.6 

10.7 

16.6 
16.0 
16.7 
14.5 

9.3 
10.1 
11.2 
8.9 

15.1 
16.3 
15.5 
16.6 

8.0 
9.8 
11.1 
10.6 

15.7 
15.2 
15.7 
16.3 

9.9 
9.9 
9.9 
9.6 

16.0 

9.9 

15.9 

9.9 

15.7 

9.8 

3d  min  

15.1 
16.7 
16.1 
16.1 

9.8 
10.6 
10.0 
9.8 

15.2 
15.1 
15.1 
16.0 

10.9 
10.0 
10.1 
10.8 

15.2 
14.0 
15.7 
15.7 

9.8 
9.7 
10.8 
11.2 

16.0 

10.1 

15.4 

10.5 

15.2 

10.4 

4th  min  

16.5 
17.2 
19.4 
17.0 

10.6 
11.3 
13.1 
11.0 

16.5 
15.5 
15.1 
16.6 

10.3 
9.5 
8.8 
10.5 

15.7 
15.6 
16.1 
15.1 

9.8 
9.9 
11.4 
10.8 

17.5 

11.5 

15.9 

9.8 

15.6 

10.4 

5th  min  .... 
6th  min  .... 

16.5 
15.5 
16.6 
16.2 

10.8 
11.0 
11.6 
9.4 

16.5 
16.5 
16.5 
17.0 

11.6 
10.5 
10.5 
10.0 

14.6 
14.7 
17.4 
15.8 

9.6 
9.3 
11.1 
11.1 

16.2 

10.7 

16.6 

10.6 

15.6 

10.3 

10.6 

16.2 
16.6 

9.3 
10.8 

15.8 
16.9 

10.4 
10.7 

186 


METABOLISM   DURING   WALKING. 


TABLE  50 Respiration-rate  and  rate  of  pulmonary  ventilation  (unreduced)  in  experiments  without  food,  for  studying 

effect  of  long  and  short  duration  of  preliminary  mouthpiece  breathing.     Subject,  E.  D.  B.,  standing.      (Values 
per  minute.) — Continued. 


Date  and 
interval 
measured. 

First  comparison. 

Second  comparison. 

Third  comparison. 

After  15 
minutes 
preliminary 
mouthpiece 
breathing. 

After  15 
seconds 
preliminary 
mouthpiece 
breathing. 

After  15 
minutes 
preliminary 
mouthpiece 

breathing. 

After  15 
seconds 
preliminary 
mouthpiece 
breathing. 

After  15 
minutes 
preliminary 
mouthpiece 
breathing. 

After  15 
seconds 
preliminary 
mouthpiece 
breathing. 

Respi- 
ration- 
rate 
(full 
min- 
utes). 

Rate 
of  pul- 
monary 
venti- 
lation 
unre- 
duced 
(full 
min- 
utes). 

Respi- 
ration- 
rate 

(# 

min.). 

Rate 
of  pul- 
monary 
venti- 
lation, 
unre- 
duced 

(X 
min.). 

Respi- 
ration- 
rate 
(full 
min- 
utes) . 

Rate 
of  pul- 
monary 
venti- 
lation 
unre- 
duced 
(full 
min- 
utes) . 

Respi- 
ration- 
rate 

(y< 

min.). 

Rate 
of  pul- 
monary 
venti- 
lation, 
unre- 
duced 

(X 
min.). 

Respi- 
ration- 
rate 
(full 
min- 
utes) . 

Rate 
of  pul- 
monary 
venti- 
lation 
unre- 
duced 
(full 
min- 
utes) . 

Respi- 
ration- 
rate 

(X 
min.). 

Rate 
of  pul- 
monary 
venti- 
lation, 
unre- 
duced 

(X 
min.). 

1916. 
Mar.  3: 

1st  min  

J14.2 
*14.2 
15.3 

14.2 

15.1 
16.7 

liters. 
9.4 

9.4 
9.5 
9.1 

9.9 
10.7 

15.7 
15.3 
14.8 
14.9 

liters. 
11.1 
10.4 
9.8 
10.2 

15.4 
14.5 
16.0 
17.4 
17.1 

liters. 
10.7 

9.7 
10.6 
11.1 

11.1 
11.0 

15.0 
15.5 
15.9 
14.4 

liters. 
11.3 
9.0 
9.8 
9.4 

15.6 
15.3 

16.1 
16.3 
16.7 

liters. 
10.0 

9.7 
10.6 
10.5 
10.7 

13.9 
14.1 
16.1 
15.2 

liters. 
9.8 
8.7 
10.4 
9.9 

15.2 

10.4 

15.2 

9.9 

14.8 

9.7 

2d  min  

14.3 
14.2 
16.1 
16.1 

9.3 
8.2 
10.4 
10.7 

13.7 
15.0 
16.6 
16.0 

8.1 
8.8 
10.7 
10.5 

15.7 
16.2 
15.8 
16.2 

9.6 
10.2 
9.7 
10.3 

15.2 

9.6 

15.3 

9.5 

16.0 

9.9 

3d  min  .... 
4th  min  .  .  . 

5th  min  .  .  . 
6th  min  .  .  . 

16.1 
15.7 
15.9 
17.0 

10.6 
9.3 
11.1 
11.6 

15.4 
15.5 
15.8 
14.2 

9.9 
9.8 
9.8 
8.5 

16.2 
16.6 
15.7 
15.7 

10.3 
10.7 
10.4 
10.0 

16.2 

10.6 

15.2 

9.5 

16.1 

10.4 

17.0 
16.0 
16.5 
17.0 

11.0 
10.0 
10.2 
10.8 

15.8 
16.7 
17.8 
18.1 

10.4 
11.3 
11.9 
11.6 

15.7 
15.8 
16.7 
15.2 

10.2 
9.5 
10.1 
10.0 

16.6 

10.5 

17.1 

11.3 

15.9 

9.9 

16.7 
14.0 
15.7 
16.7 

11.0 
9.9 
9.8 
11.5 

18.2 
16.7 
15.8 
16.6 

11.9 
11.3 
10.7 
10.9 

16.2 
16.9 
16.6 
16.6 

10.1 
11.6 
11.6 
11.0 

15.8 

10.6 

16.8 

11.2 

16.6 

11.1 

16.7 
16.7 
16.9 

12.2 
11.5 
11.5 

17.2 

17.6 
16.6 
16.8 

11.3 
10.7 
10.2 

15.7 

10.1 

1  Average  of  the  first  two  full  minutes. 


PHYSIOLOGY   OF   MOUTH-BREATHING   APPLIANCES.  187 

through  the  mouthpiece  for  approximately  15  minutes  before  the  period 
began  and  from  10  to  15  seconds  for  the  other  periods,  the  procedure 
being  similar  to  that  in  the  standing  tests.  In  these  experiments  the 
oxygen  consumption  was  large  and  hence  the  respiration-rate  and 
pulmonary  ventilation  were  correspondingly  large.  The  error  in  the 
technique  would  consequently  play  a  much  smaller  r61e  than  in  the 
standing  experiments.  Table  51  gives  the  respiration  and  ventilation 
rates  on  these  days  measured  in  minute  or  quarter-minute  intervals  for 
the  first  5  to  7  minutes  of  the  period.1  The  method  of  presentation  of 
results  is  the  same  as  in  table  50. 

The  results  show  that  the  respiration-rate  underwent  no  pronounced 
change  in  one  direction  or  the  other  in  those  periods  in  which  the  sub- 
ject had  been  breathing  through  the  mouthpiece  for  15  minutes  and  in 
which  the  measurements  were  made  on  the  per  minute  basis.  There 
was  a  slight  tendency  for  the  rate  to  be  usually  a  little  lower  than  with 
the  short  preliminary  use  of  the  mouthpiece.  In  the  quarter-minute 
measurements  there  was  more  variation,  which  was  sufficiently  small 
to  be  ascribable  to  the  error  hi  estimation  for  such  short  periods  as 
one-quarter  minute,  and  this  variation  was  not  so  uniform  as  to  indi- 
cate that  the  mouthpiece  had  more  than  a  temporary  effect.  It  would 
appear,  therefore,  that  the  practice  in  our  experiments  of  inserting 
the  mouthpiece  2  minutes  before  the  period  began  probably  gave 
ample  tune  for  the  respiration-rate  to  become  settled,  even  under 
conditions  requiring  a  great  increase  in  the  rate  of  respiration. 

The  pulmonary  ventilation  hi  the  grade-walking  experiments  varied 
considerably  from  minute  to  minute.  The  volumes  per  minute  were 
usually  larger  in  those  periods  hi  which  the  mouthpiece  had  just  been 
inserted  than  in  the  periods  in  which  it  had  been  used  for  15  minutes  or 
more,  but  this  difference  tends  to  become  smaller  as  the  experiment  pro- 
gressed. It  may  also  be  noted  that  the  ventilation  for  these  periods 
was  frequently  larger  in  the  first  and  second  quarter-minutes  than  in 
the  next  following,  indicating  a  rather  rapid  adjustment  to  the  dis- 
turbance of  the  mouthpiece  at  the  beginning  of  the  period. 

From  the  data  in  table  51,  which  usually  represent  only  5  or  6  min- 
utes of  an  8  to  11  minute  period,  the  general  impression  is  obtained 
that  in  the  majority  of  periods  the  unreduced  pulmonary  ventilation 
was  somewhat  higher  in  those  tests  with  a  short  period  of  preliminary 
mouthpiece  breathing.  This  impression  is  confirmed  by  the  average 
values  of  the  reduced  ventilation  for  the  whole  of  each  period  given 
in  table  16  (p.  78)  for  the  several  dates.  Bearing  in  mind  that  the 
comparison  periods  were  alternate,  and  that  the  first  measurement 
on  each  day  was  preceded  by  a  long  period  of  mouthpiece  breathing, 
it  is  seen  that  the  pulmonary  ventilation  was  in  all  but  two  sets  of  com- 
parisons (that  of  March  7  and  the  last  pan*  of  March  8)  larger  in  the 
period  with  the  short  preliminary  mouthpiece  breathing.  Averaging 

1The  quarter-minute  records  were  computed  to  the  full-minute  basis. 


188 


METABOLISM   DURING   WALKING. 


TABLE  51. — Respiration-rate  and  rate  of  pulmonary  ventilation  (unreduced)  in  grade-walking  experiments  without 
food,  for  studying  effect-  of  long  and  short  duration  of  preliminary  mouthpiece  breathing.  Subject,  E.  D.  B., 
SO  per  cent  grade,  at  approximately  50  meters.  (Values  per  minute.) 


Date,  and 
interval 
measured. 

First  comparison. 

Second  comparison. 

Third  comparison. 

After  15 
minutes 
preliminary 
mouthpiece 
breathing. 

After  15 
seconds 
preliminary 
mouthpiece 
breathing. 

After  15 
minutes 
preliminary 
mouthpiece 
breathing. 

After  15 
seconds 
preliminary 
mouthpiece 
breathing. 

After  15 
minutes 
preliminary 
mouthpiece 
breathing. 

• 
After  15 
seconds 
preliminary 
mouthpiece 
breathing. 

Respi- 
ration- 
rate 
(full 
min- 
utes). 

Rate 
of  pul- 
monary 
venti- 
lation 
unre- 
duced 
(full 
min- 
utes). 

Respi- 
ration- 
rate 

(X 

min.). 

Rate 
of  pul- 
monary 
venti- 
lation, 
unre- 
duced 
(tf 
min.). 

Respi- 
ration- 
rate 
(full 
min- 
utes). 

Rate 
of  pul- 
monary 
venti- 
lation 
unre- 
duced 
(full 
min- 
utes). 

Respi- 
ration- 
rate 

M 

min.). 

Rate 
of  pul- 
monary 
venti- 
lation, 
unre- 
duced 
(X 
min.). 

Respi- 
ration- 
rate 
(full 
min- 
utes) . 

Rate 
of  pul- 
monary 
venti- 
lation 
unre- 
duced 
(full 
min- 
utes). 

Respi- 
ration- 
rate 
(X 
min.). 

Rate 
of  pul- 
monary 
venti- 
lation, 
unre- 
duced 

(X 

min.). 

1916. 
Mar.  4  

27.0 
28.0 
27.5 

29.0 
27.4 

liters. 
47.0 

47.9 
49.4 

48.8 
48.5 

27.8 
27.6 
29.8 
28.8 

liters. 
51.7 
47.4 
46.2 
52.6 

29.0 
29.3 
30.0 

30.2 

29.8 
30.0 

29.0 

liters. 
45.0 

47.1 
48.4 

49.2 

49.0 
48.9 

50.0 

26.7 
28.0 
26.7 
27.3 

52.1 
50.3 
46.4 
47.5 

liters. 

liters. 

1st  min  
2d  min  

28.5 

49.5 

27.2 

49.1 

31.4 
30.3 
28.8 
31.7 

55.1 

44.7 
48.8 
53.5 

29.5 
28.4 
32.0 
26.0 

49.5 
50.7 
52.6 
47.0 

30.6 

50.5 

29.0 

50.0 

3d  min  

32.2 
30.0 
31.0 
32.0 

53.2 
49.6 
54.2 
57.4 

27.3 
28.0 
28.0 
25.8 

52.3 
49.5 
50.3 
49.8 

31.3 

53.6 

27.3 

50.5 

4th  min  .... 

5th  min.  .  .  . 
6th  min  

30.3 
36.3 
32.8 
30.8 

52.6 
52.4 
48.3 
47.0 

30.6 
28.0 
28.0 
24.0 

49.5 
45.7 
51.1 
44.9 

32.6 

50.1 

27.7 

47.8 

29.9 

50.8 

22.1 

37.5 

Mar.  6: 
1st  min  

29.3 

50.5 

28.5 
30.0 
29.5 
29.7 

57.1 
56.2 
54.1 

54.8 

28.6 
31.3 
30.7 
31.3 

56.2 
55.6 
54.2 
56.1 

29.4 

55.6 

30.5 

55.5 

PHYSIOLOGY   OF   MOUTH-BREATHING   APPLIANCES. 


189 


'ABLE  51. — Respiration-rale  and  rate  of  pulmonary  ventilation  (unreduced)  in  grade-walking  experiments  without 
food,  for  studying  effect  of  long  and  short  duration  of  preliminary  mouthpiece  breathing.  Subject,  E.  D.  B., 
30  per  cent  grade,  at  approximately  50  meters.  (Values  per  minute.) — Continued. 


Date  and 
interval 
measured. 

First  comparison. 

Second  comparison. 

Third  comparison. 

After  15 
minutes 
preliminary 
mouthpiece 
breathing. 

After  15 
seconds 
preliminary 
mouthpiece 
breathing. 

After  15 
minutes 
preliminary 
mouthpiece 
breathing. 

After  15 
seconds 
preliminary 
mouthpiece 
breathing. 

After  15 
minutes 
preliminary 
mouthpiece 
breathing. 

After  15 
seconds 
preliminary 
mouthpiece 
breathing. 

Respi- 
ration- 
rate 
(full 
min- 
utes) . 

Rate 
of  pul- 
monary 
venti- 
lation 
unre- 
duced 
(full 
min- 
utes). 

Respi- 
ration- 
rate 

(% 
min.). 

Rate 
of  pul- 
monary 
venti- 
lation, 
unre- 
duced 

(X 
min.). 

Respi- 
ration- 
rate 
(full 
min- 
utes) . 

Rate 
of  pul- 
monary 
venti- 
lation 
unre- 
duced 
(full 
min- 
utes). 

Respi- 
ration- 
rate 

(* 

min.). 

Rate 
of  pul- 
monary 
venti- 
lation, 
unre- 
duced 

(X 

min.). 

Respi- 
ration- 
rate 
(full 
min- 
utes). 

Rate 
of  pul- 
monary 
venti- 
lation 
unre- 
duced 
(full 
min- 
utes) . 

Respi- 
ration- 
rate 

(tf 

min.). 

Rate 
of  pul- 
monary 
venti- 
lation, 
unre- 
duced 
(X 
min.). 

1916. 
Mar.  6  (cont.) 

2d  min  .  .  . 

27.1 
28.2 

27.1 
26.6 

26.0 
29.5 

liters. 
50.1 

49.6 

50.0 
51.1 

45.5 
49.1 

29.7 
28.4 
31.4 
29.0 

liters. 
53.2 
48.8 
54.1 
41.6 

28.4 
27.3 

27.2 
28.4 

liters. 
52.3 

52.4 

51.1 
53.8 

31.3 
32.0 
31.3 
28.0 

53.9 
54.1 
53.0 
51.8 

liters. 

liters. 

29.6 

49.4 

30.7 

53.2 

3d  min.  ... 

28.6 
28.0 
27.3 

28.8 

53.9 
53.0 
49.5 
50.3 

30.0 
30.7 
32.5 
32.0 

55.3 
54.6 
55.0 
56.8 

28.2 

51.7 

31.3 

55.4 

4th  min. 

== 

29.8 
31.8 
32.0 
30.3 

51.5 
56.7 
55.6 
49.1 

34.5 
29.9 
30.8 
31.6 

57.9 
50.5 
55.7 
53.9 

31.0 

53.2 

31.7 

54.5 

5th  min  .... 
Mar.  7: 

1st  min  
2d  min  

30.1 
31.0 
31.1 

22.8 
26.7 
31.2 
26.6 

53.6 
55.4 
55.1 

51.5 
49.3 
50.4 
49.5 

33.6 
33.6 
32.2 

55.1 
60.7 
61.4 

26.8 

50.2 

26.2 
27.7 
29.1 
29.4 

43.8 
49.0 
49.4 
47.4 

28.1 

47.4 

190 


METABOLISM   DURING   WALKING. 


TABLE  51. — Respiration-rate  and  rate  of  pulmonary  ventilation  (unreduced)  in  grade-walking  experiments  without 
food,  for  studying  effect  of  long  and  short  duration  of  preliminary  mouthpiece  breathing.  Subject,  E.  D.  B., 
SO  per  cent  grade,  at  approximately  50  meters.  (Values  per  minute.) — Continued. 


Date  and 
interval 
measured. 

First  comparison. 

Second  comparison. 

Third  comparison. 

After  15 
minutes 
preliminary 
mouthpiece 
breathing. 

After  I.1) 
seconds 
preliminary 
mouthpiece 
breathing. 

After  15 
minutes 
preliminary 
mouthpiece 
breathing. 

After  15 
seconds 
preliminary 
mouthpiece 
breathing. 

After  15 
m  inutes 
preliminary 
mouthpiece 
breathing. 

After  15 
seconds 
preliminary 
mouthpiec 
breathing. 

Respi- 
ration- 
rate 
(full 
min- 
utes). 

Rate 
of  pul- 
monary 
venti- 
lation 
unre- 
duced 
(full 
min- 
utes). 

Respi- 
ration- 
rate 

(X 
min.). 

Rate 
of  pul- 
monary 
venti- 
lation, 
unre- 
duced 

(K 

min.). 

Respi- 
ration- 
rate 
(full 
min- 
utes) . 

Rate 
of  pul- 
monary 
venti- 
lation 
unre- 
duced 
(full 
min- 
utes). 

Respi- 
ration- 
rate 

(K 

min.). 

Rate 
of  pul- 
monary 
venti- 
lation, 
unre- 
duced 

<# 

min.). 

Respi- 
ration- 
rate 
(full 
min- 
utes). 

Rate 
of  pul- 
monary 
venti- 
lation 
unre- 
duced 
(full 
min- 
utes) . 

Respi- 
ration- 
rate 

(^ 
min.). 

Rate 
of  pul- 
monary 
venti- 
lation, 
unre- 
duced 

(X 
min.). 

1916. 
Mar.  7  (cont.) 

3d  min  

28.3 
28.0 

29.6 

28.8 
28.1 

25.5 
28.6 

liters. 
47.7 

49.8 

54.3 

52.5 
49.4 

48.9 
54.5 

28.2 
30.2 
28.7 
29.2 

liters. 
54.5 
48.9 
48.8 
51.7 

liters. 

liters. 

liters. 

liters. 

29.1 

51.0 

4th  min  .... 
5th  min  

25.8 
28.9 
27.5 
30.5 

51.3 
49.3 
51.0 
52.3 

28.2 

51.0 

29.1 
30.2 
24.6 
26.8 

50.2 
52.6 
53.2 
48.1 

27.7 

51.0 

6th  min  .... 
7th  min  

29.5 
30.8 

52.1 
59.4 

29.7 
28.0 

53.0 
58.1 

Mar.  8: 
1st  min.  .  .  . 

2d  min  

21.8 
21.8 
25.9 
27.3 

42.2 
43.8 
46.7 
51.3 

28.9 
26.8 
28.5 
28.5 

53.3 
50.2 
49.1 
52.2 

28.9 
29.1 
30.2 
32.4 

57.2 
53.6 
50.5 
55.2 

24.2 

46.0 

28.2 

51.2 

30.2 

54.1 

29.4 
30.7 

28.7 
28.4 

51.2 
58.7 
55.8 
52.5 

32.6 
34.1 
32.6 
29.8 

59.8 
60.8 
66.7 
57.1 

32.5 
31.8 
27.7 
29.6 

59.4 
63.4 
59.4 
56.5 

29.3 

54.6 

32.3 

61.1 

30.4 

59.7 

PHYSIOLOGY   OF   MOUTH-BREATHING   APPLIANCES. 


191 


TABLE  51. — Respiration-rale  and  rale  of  pulmonary  ventilation  (unreduced)  in  grade-walking  experiments  without 
food,  for  studying  effect  of  long  and  short  duration  of  preliminary  mouthpiece  breathing.  Subject,  E.  D.  B., 
30  per  cent  grade,  at  approximately  50  meters.  (Values  per  minute.) — Continued. 


First  comparison. 

Second  comparison. 

Third  comparison. 

After  15 

After  15 

After  15 

After  15 

After  15 

After  15 

minutes 

seconds 

minutes 

seconds 

minutes 

seconds 

preliminary 

preliminary 

preliminary 

preliminary 

preliminary 

preliminary 

mouthpiece 

mouthpiece 

mouthpiece 

mouthpiece 

mouthpiece 

mouthpiece 

breathing. 

breathing. 

breathing. 

breathing. 

breathing. 

breathing. 

Date  and 

interval 

Rate 

Rate 

Rate 

Rate 

Rate 

Rate 

measured. 

of  pul- 

of pul- 

of pul- 

of pul- 

of pul- 

of pul- 

Respi- 

monary 

Respi- 

monary 

Respi- 

monary 

Respi- 

monary 

Respi- 

monary 

Respi- 

monary 

ration  - 

venti- 

ration- 

venti- 

ration- 

venti- 

ration- 

venti- 

ration- 

venti- 

ration- 

venti- 

rate 

lation 

rate 

lation, 

rate 

lation 

rate 

lation, 

rate 

lation 

rate 

lation, 

(full 

unre- 

(tt 

unre- 

(full 

unre- 

(X 

unre- 

(full 

unre- 

(# 

unre- 

min- 

duced 

min.). 

duced 

min- 

duced 

min.). 

ducpd 

min- 

duced 

min.). 

duced 

utes). 

(full 

(K 

utes). 

(full 

CK 

utes). 

(full 

(% 

min- 

min.). 

min- 

min.). 

min- 

min.) 

utes). 

utes). 

utes). 

1916. 

liters. 

liters. 

liters. 

liters. 

liters. 

liters. 

Mar.  8  (cont.) 

33.5 

59.1 

33.2 

57.4 

26.9 

51.3 

33.5 

50.9 

31.6 

50.7 

27.5 

52.3 

31.8 

53.2 

34.4 

61.6 

30.3 

53.9 

30.3 

54.0 

30.0 

57.2 

31.8 

57.0 

3d  min  

29.5 

53.6 

32.3 

54.3 

31.4 

54.6 

32.3 

56.7 

30.5 

55.1 

29.1 

53.6 

32.2 

60.1 

31.1 

63.1 

30.8 

60.5 

28.7 

61.2 

26.8 

58.2 

29.2 

59.4 

30.4 

48.8 

27.8 

50.2 

30.7 

52.6 

30.7 

51.9 

34.2 

55.4 

29.9 

49.7 

4th  min  

29.5 

57.1 

30.5 

55.5 

29.5 

61.4 

30.0 

56.7 

29.5 

59.6 

30.2 

55.6 

31.3 

55.7 

34.2 

59.7 

29.4 

50.8 

28.7 

54.0 

38.5 

71.3 

30.9 

55.0 

32.4 

60.6 

34.4 

66.7 

30.4 

57.9 

32.7 

60.5 

27.1 

65.6 

27.7 

58.9 

5th  min  

29.1 

56.6 

31.3 

57.7 

30.0 

55.0 

33.6 

65.8 

29.9 

56.4 

29.6 

55.7 

6th  min  

30.2 

54.9 

all  of  the  periods  for  each  method  of  test  on  these  4  days,  we  find  the 
average  reduced  ventilation  for  the  periods  with  long  preliminary  mouth- 
piece breathing  to  be  45.8  liters  and  that  for  the  periods  with  short  pre- 
liminary breathing  to  be  46.7  liters,  with  a  difference  of  0.9  liter  or 
1.97  per  cent.  (See  table  16,  p.  78). 

At  first  sight  this  relatively  small  difference  appears  to  be  a  real  effect, 
ascribable  to  the  short  use  of  the  mouthpiece.  It  is  important  to  bear 
in  mind,  however,  that,  as  previously  pointed  out,  the  actual  amount  of 
work  performed  in  the  two  series  was  usually  somewhat  greater  in  the 
second  set  of  tests,  this  difference  being  not  far  from  1  per  cent.  Allow- 


192  METABOLISM   DURING   WALKING. 

ing  for  this  disparity  in  amount  of  work,  the  apparent  difference  be- 
tween the  series  of  tests  is  reduced  to  about  1  per  cent,  which  may  well 
be  stated  to  be  within  the  limits  of  experimental  error  and  not  suffi- 
ciently pronounced  to  indicate  a  real  physiological  difference  hi  the 
two  methods  of  preliminary  breathing. 

Owing  to  the  fact  that  a  slightly  larger  amount  of  work  was  usually 
performed  in  the  second  test  of  each  comparison  set,  i.  e.,  when  the 
experiment  was  preceded  by  but  15  seconds  of  breathing  through  the 
mouthpiece,  the  slightly  larger  oxygen  consumption  not3d  in  these 
periods  (see  tables  16  and  49)  may  be  explained  without  attributing  it 
to  the  type  of  respiration  preceding  the  experiment.  In  the  hope  that 
a  study  of  the  rate  of  oxygen  consumption  from  minute  to  minute 
might  throw  some  light  upon  the  effect  of  mouthpiece  breathing,  such 
computations  from  the  kymograph  curves  during  grade-walking  tests 
were  made.  The  results  which  are  not  tabulated,  showed  no  decided 
change  in  the  oxygen  consumption  nor  any  marked  alteration  hi  the 
rate  of  absorption  at  the  beginning  of  the  period.  The  variations  are, 
hi  a  number  of  cases,  very  large  and  are  probably  due. to  errors  in  the 
estimation  of  the  tune  from  the  slope  of  the  curve — errors  which  are 
fundamental  to  the  method.  The  evidence  of  both  the  total  per  minute 
values  in  tables  16  and  49,  and  the  values  calculated  from  the  kymo- 
graph curves,  suggests  no  appreciable  difference  in  the  rate  of  oxygen 
consumption  in  the  two  series  of  tests  which  is  not  substantially 
accounted  for  by  the  small  difference  in  the  amount  of  work  done. 

CONCLUSIONS  WITH  REGARD  TO  THE  EFFECT  OF  LONG  AND  SHORT  PRELIMINARY  MOUTH- 
PIECE BREATHING. 

A  close  study  of  the  respiration-rate,  pulmonary  ventilation,  and 
oxygen  consumption  shows  no  appreciable  differences  between  the  two 
types  of  preliminary  biea thing  other  than  what  can  reasonably  be 
ascribed  to  the  unfortunate  but  unavoidable  slight  differences  in  the 
amount  of  work  done.  On  the  other  hand,  it  is  quite  clear  that  the 
respiratory  quotient  is  materially  affected  by  the  type  of  respiration, 
particularly  in  the  walking  experiments,  being  almost  invariably  much 
lower  with  the  short  preliminary  mouthpiece  breathing. 

One  would  normally  assume  that  with  the  long  preliminary  breath- 
ing there  would  have  been  a  period  of  adjustment,  so  that  with  the  be- 
ginning of  the  metabolism  measurements  the  amount  of  carbon  dioxide 
exhaled  would  be  essentially  that  produced.  Immediately  after  the 
insertion  of  the  mouthpiece,  particularly  if  there  is  any  adjustment  of 
the  respiration  to  the  new  conditions,  as  there  usually  is,  one  can  expect 
either  an  excessive  removal  of  carbon  dioxide  due  to  pumping-out 
or  possibly  the  storage  of  carbon  dioxide  due  to  a  reduced  ventilation. 
The  former  is  usually  the  case,  and  it  can  be  easily  seen  that  the  amount 
of  carbon  dioxide  exhaled  would  then  be  larger  than  that  actually 


METABOLISM   WITH   GRADE   WALKING.  193 

produced;  consequently,  when  metabolism  measurements  are  made 
after  a  very  brief  period  of  mouthpiece  breathing,  the  respiratory  quo- 
tient would  be  large.  As  a  matter  of  fact,  under  exactly  these  condi- 
tions of  experimenting,  we  find  a  quotient  somewhat  smaller  than 
those  obtained  during  the  tests  with  a  long  preliminary  period  of  mouth- 
piece breathing.  No  simple  explanation  for  this  is  at  hand. 

These  tests  have,  however,  considerable  significance  in  that  they 
indicate  the  necessity  of  caution  in  employing  short-period  respiration 
experiments  for  the  computation  of  the  total  energy  production, 
especially  if  the  collection  of  expired  ah*  is  begun  immediately  after 
the  mouthpiece  is  inserted.  This  is  all  the  more  important,  since  there 
is  an  increasing  tendency  on  the  part  of  certain  physiologists  to  utilize 
the  carbon-dioxide  exhalation  alone  as  a  measure  of  the  metabolism.1 

When  carbon  dioxide  only  is  measured  during  periods  of  muscular 
repose,  there  is  nothing  in  our  results  to  throw  any  discredit  upon  the 
actual  determination  of  carbon  dioxide.  Indeed,  if  the  respiratory 
quotient  is  determined,  it  seems  to  be  essentially  the  same,  irrespective 
of  the  type  of  respiration.  On  the  other  hand,  in  experiments  in  which 
heavy  work  is  performed,  and  particularly  when  the  mouthpiece  is 
used,  and  the  whole  computation  of  energy  is  based  upon  carbon  dioxide 
alone,  it  is  easy  to  err  in  selecting  the  respiratory  quotient  to  be  used. 
To  be  sure,  in  many  of  these  tests  only  an  approximate  computation  of 
energy  is  desired.  It  is  important,  however,  to  bear  in  mind  that  in 
this  series  of  comparison  tests  there  is  grave  doubt  of  the  accuracy  of 
the  determination  of  the  respiratory  quotient  when  the  period  of 
measurement  is  preceded  by  a  very  short  period  of  preliminary  breath- 
ing through  the  mouthpiece. 

METABOLISM  OF  SUBJECTS  WALKING  ON  AN  INCLINE. 

In  addition  to  the  chronological  presentation  of  the  data  obtained  in 
the  grade-walking  experiments  in  tables  13  to  16,  the  metabolism 
measurements  have  also  been  assembled  in  tables  52  to  55,  to  show 
the  effect  of  the  work  performed  in  the  grade  walking  upon  the  heat- 
output  in  excess  of  both  the  standing  and  the  horizontal-walking 
requirements.  These  tables  show  the  work  performed  and  the  increase 
in  the  heat-output.  The  effect  of  grade  and  speed  upon  the  heat-out- 
put, the  physiological  factors,  and  the  efficiency  is  brought  out  by  a 
summary  of  the  data  in  table  56. 

In  considering  the  effect  of  grade  walking  upon  the  energy  output  as 
presented  in  tables  52  to  55,  it  has  been  assumed  that  the  basal  require- 
ments of  the  body  at  rest,  i.  e.,  standing,  did  not  alter  during  the  walk- 

'Benedict,  Miles,  Roth,  and  Smith,  Carnegie  Inst.  Wash.  Pub.  No.  280,  1919,  p.  119,  table  5, 
footnote  2;  Benedict  and  Johnson,  Proc.  Am.  Phil.  Soc.,  1919, 58,  p.  89;  Benedict,  Collins,  Hendry, 
and  Johnson,  N.  H.  College  of  Agr.,  Tech.  Bull.  No.  16, 1920;  Waller,  Proc.  Phyaiol.  Soc.,  1918-19, 
52,  pp.  xlviii,  1,  lix,  Ixvii,  and  Ixxii;  1919,  53,  pp.  xxiv,  xxx,  and  xliv. 


194  METABOLISM   DURING  WALKING. 

TABLE  52. — Increase  in  the  heat-output  of  A.  J.  0.  and  H.  R.  R.  during  grade  walking  in 
experiments  without  food.     (Values  per  minute.) 


Subject  and 
date. 

(a) 

Body- 
weight 
with 
clothing. 

(6) 
Grade. 

(c) 

Distance 
walked. 

(d) 

Horizon- 
tal com- 
ponent of 
distance. 

(•) 

Grade- 
lift  of 
body. 

(6Xc) 

(/) 

Work 
due  to 
grade- 
lift. 

(eXa) 

(0) 

Step- 
lift. 

(A) 

Work 
due  to 
step- 
lift. 

(0Xa) 

M 

Work 
of  total 
lift 
(work  of 
ascent). 

(f+h) 

A.  J.  O. 
Mar  2 

kg. 

p.  ct. 

meters. 
61.1 

meters. 
61.1 

meters. 
2.20 

kg.  TO. 
162.8 

meters. 

kg.  m. 

kg.  m. 

68.1 

68.1 

2.45 

181.3 

74  0 

3  6 

64.6 

64.6 

2.33 

172.1 

H.  R.  R. 

Mar.  27     .    . 

66.4 

66.0 

7.04 

516.0 

1.18 

86.5 

602.5 

66.4 

66.0 

7.04 

516.0 

1.68 

123.1 

639.1 

66.8 

66.4 

7.08 

519.0 

1.90 

139.3 

658.3 

66.6 

66.2 

7.06 

517.5 

2.26 

165.7 

683.2 

Average  .  . 

73.3 

10.6 

66.6 

66.2 

7.06 

517.1 

1.76 

128.7 

645.8 

Apr.     3   . 

61.7 

61.4 

6.29 

451.0 

1.23 

88.2 

539  2 

61.9 

61.6 

6.31 

452.4 

1.31 

93.9 

546  3 

61.8 

61.5 

6.30 

451.7 

1.29 

92.5 

544.2 

62.2 

61  9 

6  34 

454.6 

1.36 

97  5 

552  1 

Average.  . 

71.7 

10.2 

61.9 

61.6 

6.31 

452.4 

1.30 

93.0 

545.5 

Apr.  24  

63.8 

63.4 

6.70 

473.0 

1.56 

110.1 

583  1 

64.2 

63.8 

6.74 

475.8 

1.68 

118.6 

594.4 

64.1 

63.7 

6.73 

475  1 

1.76 

124  3 

599  4 

Average  .  . 

70.6 

10.5 

64.0 

63.6 

6.72 

474.6 

1.67 

117.7 

592.3 

May    1  

71.8 

71  4 

7  54 

542  9 

2  02 

145  4 

688  3 

72.5 

72.1 

7.61 

547.9 

2.15 

154.8 

702.7 

73.1 

72.7 

7.68 

553.0 

2.47 

177.8 

730  8 

73.2 

72.8 

7.69 

553.7 

2.71 

195.1 

748  8 

73.0 

72.6 

7.67 

552.2 

3  07 

221  0 

773  2 

72.9 

72.5 

7  65 

550  8 

3  27 

235  4 

786  2 

Average  .  . 

72.0 

10.5 

72.8 

72.4 

7.64 

550.1 

2.62 

188.3 

738.3 

May    8  

75.9 

75  5 

7  97 

575  4 

2  44 

176  2 

751  6 

76.1 

75.7 

7.99 

576.9 

2  86 

206.5 

783.4 

76  5 

76  1 

8  03 

579  8 

2  95 

213  0 

792  8 

76.7 

76.3 

8.05 

581  2 

3  26 

235  4 

816.6 

77.0 

76.6 

8  09 

584  1 

3  22 

232  5 

816  6 

77.0 

76.6 

8.09 

584  1 

3  47 

250  5 

834.6 

Average  .  . 

72.2 

10.5 

76.5 

76.1 

8.04 

580.3 

3.03 

219.0. 

799.3 

May  22  

66  5 

65  7 

10  17 

720  0 

1  94 

137  4 

857  4 

66.3 

65  5 

10  14 

717  9 

1  99 

140  9 

858  8 

65.7 

64  9 

10  05 

711  5 

2  11 

149  4 

860  9 

66  3 

65  5 

10  14 

717  9 

2  49 

176  3 

894  2 

Average  .  . 

70.8 

15.3 

66.2 

65.4 

10.13 

716.8 

2.13 

151.0 

867.8 

METABOLISM   WITH   GRADE   WALKING. 


195 


TABLE  52. — Increase  in  the  heat-output  of  A.  J.  0.  and  H.  R.  R.  during  grade  walking  in 
experiments  without  food.     (Values  per  minute.} — Continued. 


Subject  and 
date. 

0') 

Total 
heat 
during 
grade 
walking 
(com- 
puted). 

(*) 

Heat 
due  to 
stand- 
ing.1 

(0 

Increment 
over 
standing 
require- 
ment. 

O'-fc) 

Heat  due  to  hori- 
zontal component. 

Increment   in   heat 
over   standing   and 
horizontal  compon- 
ent due  to  grade-lift. 

(<z) 

Efficiency 
for  grade- 
lift. 

2.34X100 

(m) 

Per 

h.  kg.  in. 

(n) 

Total. 
dXaXm 

(o) 

Total. 
d-n) 

(P) 
Per  kg.  m 
of  grade- 
lift. 

oXIOOO 

P 

1000 

/ 

A.  J.  0. 
Mar.  2  

c.als. 
4.25 

cols. 

cafe. 
2.94 

gm.-cal. 

caZs. 
2.04 

2.28 

cols. 
0.90 
1..07 

gm.-cals. 
5.5 
5.9 

p.  ct. 
42.5 
39.7 

Average  .... 

H.  R.  R. 
Mar.  27  

4.66 

3.35 

4.45 

1.31 

3.14 

20.452 

2.16 

.98 

5.6 

41.8 

8.17 

6.83 

2.95 
2.95 
2.97 
2.94 

3.88 
3.87 
4.04 
4.10 

7.5 
7.5 
7.8 
7.9 

31.2 
31.2 
30.0 
29.5 

Average  .... 
Apr.     3  

8.16 
8.35 
8.40 

6.82 

7.01 

7.06 

8.26 

1.34 

6.92 

2.610 

2.96 

3.96 

7.7 

30.4 

7.47 

6.13 

2.79 
2.80 
2.80 
2.81 

3.34 
3.39 
3.47 
3.73 

7.4 
7.5 

7.7 
8.2 

31.6 
31.2 
30.4 

28.5 

Average  .... 
Apr.  24  

7.53 
7.61 

7.88 

6.19 

6.27 

6.54 

7.62 

1.34 

6.28 

2.634 

2.80 

3.48 

7.7 

30.4 

7.28 

5.94 

2.56 
2.58 
2.58 

3.38 
3.54 
3.45 

7.1 
7.4 
7.3 

33.0 
31.6 
32.0 

Average  .... 
May  1   

7.46 
7.37 

6.12 

6.03 

7.36 

1.34 

6.02 

2.574 

2.57 

3.45 

7.3 

32.0 

8.17 

6.83 

3.18 
3.21 
3.23 
3.24 
3.23 
3.23 

3.65 
3.76 
3.92 
4.32 
4.35 
4.24 

6.7 
6.9 
7.1 
7.8 
7.9 
7.7 

34.9 
33.9 
33.0 
30.0 
29.6 
30.4 

Average  .... 
May     8  

8.31 
8.49 
8.90 
8.92 
8.81 

6.97 

7.15 

7.56 

7.58 

7.47 

8.59 

1.34 

7.25 

'.618 

3.22 

4.03 

7.3 

32.1 

8.54 

7.20 

3.37 
3.38 
3.40 
3.40 
3.42 
3.42 

3.83 
3.96 
4.13 
4.30 
4.44 
4.52 

6.7 
6.9 
7.1 

7.4 
7.6 

7.7 

34.9 
33.9 
33.0 
31.6 
30.8 
30.4 

Average  .... 
May  22  

8.68 
8.87 
9.04 
9.20 
9.28 

7.34 

7  53 

7.70 

7  86 

7  94 

8.93 

1.34 

7.59 

'.618 

3.40 

4.19 

7.2 

32.5 

9.89 

8.55 

2.87 
2.87 
2.84 
2.87 

5.68 
5.68 
5.75 
5.92 

7.9 
7.9 
8.1 
8.2 

29.6 
29.6 
28.9 
28.5 

Average  .... 

9.89 
9.93 
10.13 

8.55 

8.59, 
8.79 

9.95 

1.34 

8.61 

'.618 

2.86 

5.75 

8.0 

29.3 

1General  averages  for  these  subjects.     See  last  column  of  table  3,  p.  43. 

2Average  for  day.     See  column  i  of  table  29,  p.  120. 

"General  average  used,  as  no  horizontal  walking  was  done  on  these  days. 


196 


METABOLISM   DURING   WALKING. 


TABLE  53. — Increase  in  the  heat-output  of  T.  H.  H.  during  grade  walking  in  experiments 
without  food.     (Values  per  minute.) 


Subject  and 
date. 

(a) 

Body- 
weight 
with 
clothing. 

(*>) 
Grade. 

(c) 

Distance 
walked. 

WJ 

Horizon- 
tal com- 
ponent of 
distance. 

(«) 

Grade- 
lift  of 
body. 

(bXc) 

(/) 

Work 
due  to 
grade- 
lift. 

(eXa) 

(a) 

Step- 
lift. 

00 

Work 
due  to 
step- 
lift. 

(0Xa) 

« 
Work 
of  total 
lift 
(work  of 
ascent). 
(f+h) 

Mar  24 

kg. 

p.ct. 

meters. 
63.4 

meters. 
63.1 

meters. 
6.53 

kg.  m. 
367.0 

meters. 
2.49 

kg.  m. 
139.9 

kg.  m. 
506.9 

62.3 

62.0 

6.42 

360.8 

2.48 

139.4 

500.2 

62.1 

61.8 

6.40 

359.7 

2.46 

138.3 

498.0 

Average  .  . 

56.2 

10.3 

62.6 

62.3 

6.45 

362.5 

2.48 

139.2 

501.7 

Mar.  26 

63.4 

63.1 

6.53 

366.3 

2.80 

157.1 

523.4 

64.3 

64.0 

6.62 

371.4 

2.69 

150.9 

522.3 

64.1 

63.8 

6.60 

370.3 

2.77 

155.4 

525.7 

63.9 

63.6 

6.58 

369.1 

2.62 

147.0 

516.1 

Average  .  . 

56.1 

10.3 

63.9 

63.6 

6.58 

369.3 

2.72 

152.6 

521.9 

Mar.  30  

62  1 

61.8 

6.33 

355.7 

2.45 

137.7 

493.4 

61  0 

60.7 

6.22 

349.6 

2  40 

134.9 

484.5 

61.3 

61.0 

6.25 

351.3 

2.48 

139.4 

489.7 

Average  .  . 

56.2 

10.2 

61.5 

61.2 

6.27 

352.2 

2.44 

137.3 

489.2 

Apr.     6  

62.3 

62.0 

6.48 

367.4 

2.48 

140.6 

508.0 

63.2 

62.9 

6.57 

372.5 

2.51 

142.3 

514.8 

63.7 

63.4 

6.62 

375.4 

2.68 

152.0 

527.4 

Average.  . 

56.7 

10.4 

63.1 

62.8 

6.56 

371.8 

2.56 

145.0 

516.7 

Apr.     6  

58  4 

58.1 

6.07 

338.1 

2.30 

128.1 

466.2 

59  3 

59.0 

6.17 

343  .  7 

2.44 

135.9 

479.6 

60.2 

59.9 

6.26 

348.7 

2.50 

139.3 

488.0 

59  4 

59.1 

6.18 

344.2 

2.53 

141.0 

485.2 

60.1 

59.7 

6.25 

348.1 

2.56 

142.6 

490.7 

60.4 

60.1 

6.28 

349.8 

2.62 

145.9 

495.7 

Average  .  . 

55.7 

10.4 

59.6 

59.3 

6.20 

345.4 

2.49 

138.8 

484.2 

Apr.     7  

56  1 

55.8 

5.83 

324.7 

2  34 

130  3 

455  0 

56.4 

56.1 

5.87 

327.0 

2.24 

124.8 

451.8 

56.3 

56.0 

5.86 

326.4 

2.34 

130.3 

456.7 

56  6 

56.3 

5.89 

328.1 

2.42 

134.8 

462.9 

56  5 

56.2 

5.88 

327.5 

2.46 

137  0 

464.5 

57  2 

56.9 

5.95 

331.4 

2.46 

137  0 

468.4 

57.6 

57.3 

5.99 

333.6 

2.46 

137.0 

470.6 

Average  .  . 

55.7 

10.4 

56.7 

56.4 

5.90 

328.4 

2.39 

133.0 

461.6 

Apr.     8  

67  8 

67  4 

7  05 

389  9 

2  83 

156  5 

546  4 

68  0 

67.6 

7.07 

391.0 

2  84 

157  1 

548  1 

67  5 

67  1 

7.02 

388.2 

2  94 

162  6 

550  8 

67.9 

67.5 

7.06 

390.4 

3.23 

178.6 

569.0 

68  6 

68.2 

7.13 

394.3 

3.31 

183.0 

577.3 

69.0 

68.6 

7.18 

397.1 

3.29 

181.9 

579.0 

Average.  . 

55.3 

10.4 

68.1 

67.7 

7.09 

391.8 

3.07 

170.0 

562.4 

Apr.  15  

' 

63  9 

63  6 

6  58 

374  4 

2  79 

158  8 

533  2 

65  0 

64  6 

6  70 

381  2 

2  89 

164  4 

545  6 

64  8 

64  5 

6  64 

377  8 

2  80 

159  3 

537  1 

65  0 

64  7 

6  66 

379  0 

2  90 

165  0 

544  0 

65  4 

65.1 

6  71 

381  8 

2  94 

167.3 

549.1 

65.9 

65.6 

6.76 

384.6 

2.96 

168.4 

553.0 

Average.  . 

56.9 

10.3 

65.0 

64.7 

6.68 

379.8 

2.88 

163.9 

543.7 

METABOLISM   WITH   GRADE   WALKING. 


197 


TABLE  53. — Increase  in  the  heat-output  of  T.  H.  H.  during  grade  walking  in  experiments 
without  food.     (Values  per  minute) — Continued. 


Subject  and 
date. 

0") 
Total 
heat 
during 
grade 
walking 
(com- 
puted) . 

(k) 

Heat 
due  to 
stand- 
ing. 

(0 

Increment 
over 
standing 
require- 
ment. 

(j-k) 

Heat  due  to  hori- 
zontal component. 

Increment  in  heat  over 
standing  and  horizon- 
tal component  due  to 
grade-lift. 

(a) 

Efficiency 
for  grade- 
lift. 

2.34X100 

(w) 

Per 

h.  kg.  m. 

(n) 
Total. 
dXaXm 

(o) 
Total. 
(*-n) 

(P) 
Per  kg.m.  of 
grade-lift. 
oXIOOO 

1000 

/ 

P 

Mar.  24 

cols. 
5.61 

cats. 

cals. 
4.50 
4  62 

gm.-cal. 

cals. 
1.99 
1.96 
1.95 

cals. 
2.51 
2.66 
2.55 

gm.-cals. 
6.8 
7.3 
7.1 

p.  ct. 
34.4 
32.1 
33.0 

Average  .... 
Mar.  26  

Average  .... 
Mar.  30  

Average  .... 
Apr.     5  

Average  .... 
Apr.     6  

Average  .... 
Apr.     7  

5.73 
5.61 

4.50 

5.64 

4.  11 

4.53 

20.562 

1.97 

2.56 

7.1 

33.0 

5.79 
5.87 
5.97 
6.07 

4.68 
4.76 
4  86 

1.98 
2.01 
2.00 
1.99 

2:70 

2.75 
2.86 
2.97 

7.4 
7.5 

7.7 
8.1 

31.6 
31.2 
30.4 
28.9 

4.96 

5.93 

4.  11 

4.82 

2.559 

1.99 

2.83 

7.7 

30.4 

5.80 
5.70 
5.91 

4.69 
4.59 
4.80 

2.10 
2.07 
2.08 

2.59 
2.52 
2.72 

7.3 

7.2 

7.7 

32.1 
32.5 
30.4 

5.80 

4.  11 

4.69 

2.606 

2.08 

2.61 

7.4 

31.6 

6.03 
6.28 
6.40 

4.92 
5.17 

2.24 
2.27 
2.29 

2.68 
2.90 
3.00 

7.3 
7.8 
8.0 

32.1 
30.0 
29.3 

5.29 

6.24 

»1.11 

5.13 

2.637 

2.27 

2.86 

7.8 

30.0 

5.59 
5.62 
5.70 
6.04 
5.94 
6.11 

4.48 
4.51 
4.59 

1.87 
1.90 
1.93 
1.91 
1.93 
1.94 

2.61 
2.61 
2.66 
3.92 
2.90 
3.06 

7.7 
7.6 
7.6 
8.8 
8.3 
8.7 

30.4 
30.8 
30.8 
26.6 

28.2 
26.8 

4.93 

4.83 

5.00 

5.8.3 

4.  11 

4.72 

3.579 

1.91 

2.81 

8.1 

28.9 

5.45 
5.50 
5.47 
5.56 
5.57 
5.79 
5.80 

4.34 
4.39 

1.80 
1.83 
1.81 
1.82 
1.81 
1.84 
1.85 

2.54 
2.55 
2.55 
2.63 
2.65 
2.84 
2.84 

7.8 
7.8 
7.5 
7.7 
8.1 
8.6 
8.5 

30.0 
30.0 
31.2 
30.4 
28.9 
27.2 
27.5 

Average  .... 
Apr.     8  

Average  .... 
Apr    15 

4.36 

4.45 

4.46 
4.68 

4.69 

5.59 

U.ll 

4.48 

3.579 

1.82 

2.66 

8.1 

28.9 

6.34 
6.23 
6.33 
6.40 
6.48 
6.58 

5.23 
5.12 

2.16 
2.16 
2.15 
2.16 
2.18 
2.20 

3.07 
2.96 
3.07 
3.13 
3.19 
3.27 

7.9 
7.6 
7.9 
a.O 
8.1 
8.2 

29.6 
30.8 
29.6 
29.3 
28.9 
28.5 

5.22 

5.29 

5.37 

5.47 

6.39 

4.11 

5.28 

3.579 

2.17 

3.11 

7.9 

29.6 

5.70 
5.84 
5.79 
5.81 
5.91 
5.98 

4.59 

2.14 
2.13 
2.12 
2.13 
2.14 
2.16 

2.45 
2.60 
2.56 
2.57 
2.66 
2.71 

6.6 
6.8 
6.8 
6.8 
7.0 
7.0 

35.5 
34.4 
34.4 
34.4 
33.4 
33.4 

Average  .... 

4.73 



4.68 
4.70 

4.80 

4.87 

5.84 

4.11 

4.73 

'.579 

2.13 

2.60 

6.8 

34.4 

1  Average  of  the  values  obtained  in  all  standing  experiments  with  this  subject.     (See  last 

column  of  table  4,  p.  44.) 

*Average  value  obtained  on  the  day  of  the  experiment.     (See  column  i,  table  30,  p.  122.) 
'Average  of  the  values  obtained  in  all  horizontal-walking  experiments  with  this  subject.    (See 

column  i,  table  30,  p.  122.) 


198  METABOLISM   DURING  WALKING. 

ing,  and  that  the  excess  energy  expended  for  the  grade  walking  was  the 
energy  required  to  lift  the  body  to  a  vertical  elevation,  this  elevation 
being  computed  from  the  grade  of  the  treadmill  and  the  linear  dis- 
tance walked  at  this  grade;  also  that  the  energy  expended  for  the 
horizontal  component  of  this  linear  distance  was  the  same  per  meter 
as  that  determined  in  the  horizontal-walking  experiments.  Still 
another  assumption  is  made,  namely,  that  during  grade  walking  there 
is  a  certain  amount  of  step-lift,  which  constitutes  a  varying  amount  of 
work  to  be  added  to  the  work  of  grade  elevation.  An  effort  was  made 
to  measure  this  step-lift  and  to  compute  the  work  which  it  represented 
and  the  energy  which  it  required.  It  is  necessary  to  consider,  there- 
fore, (1)  the  work  due  to  the  grade  of  the  treadmill,  which  is  referred  to 
as  the  work  of  grade-lift;  (2)  the  work  due  to  the  heel-and-toe  action, 
i.  e.,  the  step-lift;  and  (3)  the  sum  of  these  two,  which  constitutes  the 
work  of  ascent.  As  was  the  case  in  the  horizontal-walking  experiments, 
the  measured  value  of  the  step-lift  is  of  somewhat  doubtful  dependa- 
bility; this  in  turn  affects  the  total  amount  of  work,  the  so-called  work 
of  ascent.  The  measure  of  the  work  due  to  grade-lift  is,  however, 
believed  to  be  accurate.  It  will  therefore  be  considered  more  fully 
than  the  other  factors,  and  has  been  used  as  the  basis  of  the  curves  pre- 
sented in  this  section. 

The  method  by  which  the  grade-lift  was  measured  and  the  computa- 
tion of  the  horizontal  component  of  the  distance  walked  have  been 
explained  on  page  29.  (See  also  fig.  6.)  With  the  low  grades  this 
latter  value,  shown  in  column  d  of  tables  52  to  55,  differs  but  little 
from  the  total  distance  walked. 

The  values  used  for  the  standing  requirement,  which  have  been  de- 
ducted from  the  total  energy  to  find  the  energy  requirement  for  walk- 
ing, are  generally  the  average  values  for  a  period  of  days,  although  the 
average  found  for  that  particular  day  has  been  used  in  many  instances. 
The  values  employed  are,  in  all  cases,  indicated  by  footnotes  in  the 
tables.  In  determining  the  energy  to  be  deducted  for  the  horizontal 
component,  use  has  been  made  of  the  increment  per  horizontal  kilo- 
grammeter,  if  found  for  the  day  of  experiment,  and,  if  not,  an  average 
value  was  employed.  When  any  wide  deviation  appeared  in  the  values 
for  a  subject  during  the  period  of  study,  as  was  the  case  with  E.  D.  B., 
the  average  value,  if  employed,  is  that  which  in  our  judgment  more 
nearly  represents  the  average  increment  at  the  time  of  the  grade- 
walking  experiments. 


METABOLISM   WITH   GRADE   WALKING. 


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9 

I-t          lH 

CO  »O  CO  CO  CO  t*1*  CO 

CO  CO  CO  OS  CO  N  CO 

CO  CO-*  CO  CO  CO  CM 

CM^COCN^rHCM 

CO  CON 

COCON 

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EEE2E2EEZ: 

ooja><Do;a,cjoo 

EEEEEEEES 

OiOOOlOOlOOlO 
T*Tj<lOCOCOr-t—  XX 

..  oooocoooo. 

EEEEEEEE 

OUiOCOiOOiO 

T^Tj^iocor^t—  xx 

.00000000. 

.  co  •*  T)<  10  <o  t-  r~  x 

IH     irt     IH     t-l     IH     id     I-t 

iiilill 

OOiOOiOOiO 
xjt  iO  iO  t-  1~  X  X 

•3S55  °  °  °  • 

EEEESEE 

1C  O  O  IO  O  iO  O 
•*  >O  CO  CO  t~  t—  X 

•  &  6  6  C  6  8 

IEEEEES 

iOOiOO"OO>O 
•^f  iO  iO  CO  CO  t*  t— 

'23S2S  °  °  • 

45  to  50  meters.  .  .  . 
55  to  60  meters.  .  .  . 
60  to  65  meters.  .  .  . 

50  to  55  meters'  .  .  . 
55  to  60  meters.  .  .  . 
65  to  70  meters  .  .  . 

40  to  45  meters.  .  .  . 

224 


METABOLISM   DURING  WALKING. 


CARBON-DIOXIDE  ELIMINATION  AND  OXYGEN  CONSUMPTION  DURING  GRADE  WALKING. 
The  total  carbon  dioxide  eliminated  and  oxygen  consumed  during 
the  grade-walking  experiments,  as  given  chronologically  in  tables  13 
to  16,  show  variations  for  the  different  periods  of  the  individual  days, 
but  when  we  take  into  consideration  the  fact  that  the  speed  also  varied 
to  a  certain  extent  for  the  different  periods  on  each  day,  these  variations 
hi  the  carbon  dioxide  and  oxygen  appear  to  have  no  general  significance, 
especially  as  they  have  no  uniform  relationship  with  the  variations  in 
the  speed.  On  the  other  hand,  when  the  data  are  grouped  according 
to  grade  and  speed,  as  is  done  in  table  56,  we  find  with  any  one  grade 
that  when  the  speed  increases,  that  is,  when  the  work  performed  in- 
creases, there  is  likewise  an  increase  in  the  carbon  dioxide  and  oxygen. 
We  also  find  that  both  the  carbon  dioxide  and  oxygen  with  a  low  speed 
and  high  grade  are  lower  than  when  the  same  amount  of  work  is  accom- 
plished with  a  high  speed  and  a  low  grade.  This  is  also  shown  in  the 
curves  in  figures  16  to  19,  which  are  discussed  later. 

TABLE  57. — Metabolism  of  W.  K.  and  E.  D.  B.,  with  maximum  amount  of  work  performed. 

(Values  per  minute.) 


Subject. 

Date. 

Work 
performed. 

Carbon 
dioxide. 

Oxygen. 

Increase  over  stand- 
ing requirement. 

Carbon 
dioxide. 

Oxygen. 

W.  K.. 

June  23,  1915 
Feb.  22,1916 
Mar.    6,1912* 
May  10,  1914s 

kg.m. 
!891 
!1,569 
1,024 

c.  c. 
2,152 
3,017 
2,751 
2,101 

c.  c. 
2,094 
3,132 
2,976 
,2,384 

p.  ct. 
1,057 
1,416 
1,180 

877 

p.  ct. 
818 
1,205 
1,110 
869 

E.  D.  B. 

M.  A.  M  

'Work  due  to  grade-lift.     See  column  /,  tables  54  and  55. 

*See  Benedict  and  Cathcart,  Carnegie  Inst.  Wash.  Pub.  No.  187,  1913,  p.  64,  table  74,  and  p. 
124,  table  116.  The  subject  rode  a  bicycle  ergometer. 

3See  Benedict  and  Murschhauser,  Carnegie  Inst.  Wash.  Pub.  No.  231,  1915,  p.  59.  Standing 
values  for  same  day  for  carbon  dioxide  and  oxygen  (215  c.  c.  and  246  c.  c.,  respectively)  used  as 
base  for  computing  increase  for  this  period,  also  for  March  6,  1912.  The  subject  walked  on  a 
level. 

The  maximum  daily  averages  for  the  two  subjects  who  did  the 
largest  amounts  of  work  (W.  K.  and  E.  D.  B.)  are  given  in  table  57. 
For  comparison,  the  maximum  performance  of  M.  A.  M.  on  a  bicycle 
ergometer  in  the  study  of  Benedict  and  Cathcart,1  and  of  the  same 
subject  walking  on  a  level  in  the  study  of  Benedict  and  Murschhauser2 
are  included  in  the  table.  It  should  be  stated,  however,  that  whereas 
the  values  for  W.  K.  and  E.  D.  B.  represent  an  average  of  data  ob- 
tained in  two  periods  of  approximately  10  minutes  each,  the  figures  for 

'Benedict  and  Cathcart,  Carnegie  Inst.  Wash.  Pub.  No.  187,  1913,  p.  64,  table  74,  and  p.  124, 
table  116. 

'Benedict  and  Murschhauser,  Carnegie  Inst.  Wash.  Pub.  No.  231,  1915,  p.  59. 


METABOLISM   WITH    GRADE   WALKING. 


225 


M.  A.  M.  in  both  cases  represent  measurements  in  only  one  period  of 
the  same  length.  By  comparing  these  maximum  values  with  the 
average  standing  requirements  for  the  two  subjects  W.  K.  and  E.  D.  B. 
(see  tables  5  and  6,  pp.  44  and  46),  we  find  a  percentage  increase  in  the 
carbon-dioxide  elimination  and  oxygen  consumption  of  1,057  and 
818  per  cent,  respectively,  for  W.  K.,  and  1,416  and  1,205  per  cent, 
respectively,  for  E.  D.  B. 

In  figures  16  and  17  the  total  carbon-dioxide  production  per  minute 
versus  the  kilogrammeters  of  work  is  plotted  for  the  different  grades  for 
four  of  the  subjects.  From  these  curves  it  may  be  seen  that  the  car- 
bon-dioxide production  per  minute  for  all  of  the  subjects  increased 
uniformly  with  the  increase  in  the  amount  of  work  performed.  With 
both  W.  K.  and  E.  D.  B.  the  curves  for  the  various  grades  show  a 
general  parallelism.  The  significant  feature  of  these  curves  is,  however, 
their  relative  position,  in  that  the  curve  for  the  higher  grade  always 


CO2 
c.  c. 
2200 

2000 
1800 
1600 
1400 
1200 
1000 
800 
600 

f 

/ 

/ 

/ 

jz 

.  / 

// 

•//, 

j/! 

/ 

'/. 

y/ 

*   TKH.  10.0* 
e   RR.R.  10:0 
*             15.0 
*     W.K.     3.6^.9 
o              10.0 
0              15.0 
•             20.0 
V             25.0 

</ 

< 

!/* 

# 

/ 

Kg.ms.  200 


400 


600 


800 


1000 


FIQ.  16. — Total  carbon-dioxide  production  of  T.  H.  H., 
H.  R.  R.,  and  W.  K.,  referred  to  kilogrammeters  of 
work  performed  in  walking  on  different  grades.  (Val- 
ues per  minute.) 

lies  beneath  the  curve  for  the  next  lower  grade.  For  instance,  in  the 
curves  for  W.  K.  in  figure  16,  that  for  the  25  per  cent  grade  lies  below 
the  curve  for  the  20  per  cent  grade,  the  curve  for  the  20  per  cent  grade 
lies  below  that  for  the  15  per  cent  grade,  etc.  As  the  work  done  is  the 
product  of  the  grade,  body-weight,  and  distance  walked  per  minute, 
and  the  body- weight  may  be  taken  as  constant,  when  the  same  amount 
of  work  is  performed  with  two  different  grades,  this  is  due  to  a  change 
in  the  speed  of  walking.  The  relative  position  of  these  curves  shows, 
therefore,  that  while  the  man  were  able  to  accomplish  identical  amounts 
of  work  on  the  high  and  low  grades  by  walking  more  rapidly  on  the  low 


226 


METABOLISM   DURING   WALKING. 


grade,  in  the  performance  of  this  work  there  was  less  economy  in  the 
metabolism  with  the  lower  grade. 

Thus,  from  the  curves  for  W.  K.,  we  find  that  in  performing  700 
kg.  m.  of  work  on  a  25  per  cent  grade,  he  would  produce  1,540  c.  c.  of 
carbon  dioxide,  while  for  the  same  amount  of  work  on  a  20  per  cent 
grade  the  carbon-dioxide  production  would  be  1,665  c.  c.  A  like 
relation  is  seen  to  exist  in  the  carbon-dioxide  curves  for  E.  D.  B.,  400 
kg.  m.  of  work  on  a  15  per  cent  grade  costing  920  c.  c.  of  carbon  dioxide, 
whereas  on  a  10  per  cent  grade  it  would  cost  E.  D.  B.  1,030  c.  c. 


CO, 
c.c. 

3000 


2800 
2600 
2400 
2200 
2000 
1800 


1600 
1400 
1200 
1000 
800 


600 


400 


200 


400 


600 


800 


1000 


1200 


1400 


1600 


Kgjns. 

FIG.  17. — Total  carbon-dioxide  production  of  E.  D.  B.,  referred  to  kilogrammeters 
of  work  performed  in  walking  on  different  grades.     (Values  per  minute.) 

The  oxygen  consumption  per  minute  for  the  same  four  men  has  also 
been  plotted  on  the  basis  of  kilogrammeters  of  work,  and  the  curves  are 
given  in  figures  18  and  19.  The  general  picture  of  the  relationships  is 
similar  to  that  in  figures  16  and  17,  with  reasonable  uniformity  between 
the  increase  in  the  oxygen  consumption  and  the  increase  in  the  amount 
of  work  accomplished.  The  curves  for  E.  D.  B.  for  the  higher  grades 
(25  per  cent  and  over)  exhibit  a  tendency  to  change  slightly  in  direction 
as  compared  with  those  for  the  lower  grades. 

While  the  range  of  work  with  W.  K.  was  less  than  with  E.  D.  B.,  the 
single  curve  for  this  subject  above  20  per  cent  (that  for  a  25  per  cent 
grade)  indicates  a  similar  tendency  to  change  in  direction  at  this  point. 
The  relative  position  of  the  curves  with  both  subjects  is  usually  like 
that  found  for  the  carbon-dioxide  curves.  With  E.  D.  B.,  however, 


METABOLISM   WITH   GRADE   WALKING. 


227 


oa 

c.  c. 
2300 

2100 
1900 
1700 
1500 
1300 
1100 
900 
700 

2 

/  ' 

/ 

o      / 

7 

'/. 

/ 

f 

f 

tftf 

r 

•  -T.HH.  10.0% 
O.H.R.R.  10.0 
A-           15.0 
X.W.K.    3.6,19 
o  .           10.0 
O-          15.0 
•  '          20.0 
V.          25.0 

'fit 

fO 

< 

/do 

dfo 

/ 

Kg.ms.    100 


300 


500 


700 


900 


FIG.  18. — Total  oxygen  consumption  of  T.  H.  H.,  H.  R.  R., 
and  W.  K.,  referred  to  kilogrammeters  of  work  per- 
formed in  walking  on  different  grades.  (Values  per 
minute.) 


3100. 
2900. 
2700. 
2500. 
2300. 
2100. 
1900. 
1700. 
1500. 
1300. 
1100. 

900. 

700. 

500 


Kg.ms. 


200 


400 


600 


800 


1000 


1200 


1600 


FIG.  19. — Total  oxygen  consumption  of  E.  D.  B.,  referred  to  kilo- 
grammeters of  work  performed  in  walking  on  different  grades. 
(Values  per  minute.) 


228  METABOLISM   DURING   WALKING. 

it  may  be  seen  that  the  curve  for  the  35  per  cent  grade  lies  above 
that  for  the  30  per  cent  grade  instead  of  slightly  below  it.  This 
reverse  in  relationship  is  also  found  for  the  lowest  point  on  the  25  per 
cent  curve  and  for  the  two  points  for  the  45  per  cent  grade,  but  these 
exceptions  do  not  give  sufficient  cause  for  questioning  the  other  curves, 
since  the  carbon-dioxide  and  oxygen  curves  for  both  subjects  indicate 
that  a  definite  amount  of  work  can  be  performed  at  an  optimum  by 
intensifying  the  grade  and  lowering  the  speed.  The  general  picture  of 
these  curves  for  both  carbon  dioxide  and  oxygen  is  that  the  relationship 
between  the  rate  of  increase  in  the  metabolism  and  in  the  work  per- 
formed is  uniform  within  the  ranges  here  reported. 

The  curves  for  the  oxygen  consumption  of  W.  K.  and  E.  D.  B.  in 
relation  to  the  kilogrammeters  of  work  are  also  presented  in  figures  23 
and  24  (pp.  236  and  237),  as  plotted  from  the  averages  given  in  table  56, 
in  which  the  data  are  grouped  according  to  grade  and  speed.1 

The  curve  for  W.  K.  (fig.  23)  indicates  a  slight  change  in  trend  in  the 
region  of  200  kg.  m.,  but  that  of  E.  D.  B.  (fig.  24)  is  linear  throughout 
the  entire  length.  From  the  course  of  the  curve  for  E.  D.  B.,  425  c.  c. 
per  minute  would  appear  to  be  the  requirement  for  maintenance,  hori- 
zontal increment,  step-lift,  etc.,  upon  which  the  requirement  for  grade 
work  per  se  is  superimposed.  The  slope  of  the  curve  shows  that  on  the 
average  each  kilogrammeter  of  grade  work  required  an  oxygen  con- 
sumption of  1.7  c.  c.  throughout  the  range  of  E.  D.  B.'s  endurance. 
The  break  in  the  curve  for  W.  K.  at  200  kg.  m.  makes  an  estimate  of 
his  requirements  uncertain,  but  above  300  kg.  m.  his  curve  is  linear, 
and  from  the  slope  of  this  part  of  the  curve  it  would  appear  that  the 
oxygen  consumption  was  1.95  c.  c.  for  each  kilogrammeter  of  work  in 
the  range  studied,  i.  e.,  between  100  and  900- kg.  m. 

From  the  curves  in  figures  23  and  24  an  estimate  has  been  made  for 
both  W.  K.  and  E.  D.  B.  of  the  average  oxygen  consumption  for  in- 
creasing amounts  of  work  performed.  These  figures  are  recorded  in 
the  second  column  of  tables  58  and  59.  The  total  and  percentage 
increases  over  the  standing  requirement  are  likewise  given.  These 
tables  show  that,  in  the  range  covered,  the  increase  in  the  total  amount 
of  oxygen  consumed  and  both  the  total  and  the  percentage  incrsases 
over  the  standing  requirement  were  larger  for  W.  K.  than  for  E.  D.  B. 
Thus,  for  900  kg.  m.  (the  maximum  amount  of  work  done  by  W.  K.), 
the  total  oxygen  consumption  over  the  standing  requirement  was  1,982 
c.  c.,  or  869  per  cent  above  the  standing  value  for  W.  K.,  while  for 
E.  D.  B.  for  an  equal  amount  ol  work,  the  corresponding  values  were 
1,740  c.  c.  of  oxygen  and  725  per  cent  above  the  standing  requirement. 
It  is  also  seen  from  these  tables  that  it  cost  more  per  unit  of  100  kg.  m. 

'The  curves  sketched  through  the  points  in  these  figures  and  also  those  in  figures  28  and  29 
for  respiration-rate,  pulmonary  ventilation,  and  pulse-rate,  represent  the  average  of  estimates 
made  by  three  members  of  the  Laboratory  staff. 


METABOLISM   WITH   GRADE   WALKING. 


229 


of  "work  in  the  amount  of  oxygen  consumed  to  perform  smaller 
amounts  of  work  than  it  did  for  a  larger  amount.  Thus,  per  100 
kg.  m.  of  work  W.  K.  required  316  c.  c.  of  oxygen  above  the  standing 
requirement  when  200  kg.  m.  of  work  were  performed  per  minute  and 
but  220  c.  c.  when  900  kg.  m.  of  work  were  performed.  That  is,  if 

TABLE  58. — Oxygen  consumption  of  W.  K.  with  increasing  amounts  of  work  in  grade-walking 
experiments  without  food.     (Values  per  minute.)1 


Increase  over  stand- 

Percentage increase 

ing  requirement 

over  standing 

Kg.m.  of 

Oxygen 

(228  c.  c.). 

requirement. 

work 

consump- 

done. 

tion. 

Total. 

Per  100 
kg.m. 

Total. 

Per  100 
kg.m. 

c.  c. 

c.  c. 

c.  c. 

p.  ct. 

p.  ct. 

200 

860 

632 

316 

277 

139 

300 

1,030 

802 

267 

352 

117 

400 

1,230 

1,002 

251 

439 

110 

500 

1,420 

1,192 

238 

523 

105 

600 

1,620 

1,392 

232 

610 

102 

700 

1,810 

1,582 

226 

694 

99 

800 

2,000 

1,772 

222 

777 

97 

900 

2,210 

1,982 

220 

869 

97 

Estimated  from  curve  in  fig.  23,  p.  236. 

TABLE  59. — Oxygen  consumption  of  E.  D.  B.  with  increasing  amounts  of  work  in  grade- 
walking  experiments  without  food.     (Values  per  minute.)1 


Increase  over  stand- 

Percentage increase 

ing  requirement. 

over  standing 

Kg.  m.  of 

Oxygen 

(240  c.  c.). 

requirement. 

work 

consump- 

done. 

tion. 

Total. 

Per  100 

kg.  m. 

Total. 

Per  100 
kg.  m. 

c.  c. 

e.  c. 

c.  c. 

p.  ct. 

p.  ct. 

100 

600 

360 

360 

150 

150 

200 

775 

545 

273 

227 

114 

300 

940 

700 

233 

292 

97 

400 

1,120 

880 

220 

367 

92 

500 

1,290 

1,050 

210 

438 

88 

600 

1,460 

1,220 

204 

508 

85 

700 

1,630 

1,390 

199 

579 

83 

800 

1,805 

1,565 

196 

652 

82 

900 

1,980 

1,740 

193 

725 

80 

1,000 

2,150 

1,910 

191 

796 

80 

1,100 

2,330 

2,090 

190 

871 

79 

1,200 

2,500 

2,260 

188 

942 

78 

1,300 

2,670 

2,430 

187 

1,013 

78 

1,400 

2,845 

2,605 

186 

1,085 

78 

1,500 

3,010 

2,770 

185 

1,154 

77 

1,600 

3,190 

2,950 

184 

1,229 

77 

Estimated  from  curve  in  fig.  24,  p.  237. 


230 


METABOLISM   DURING   WALKING. 


the  total  energy  expended  above  the  standing  requirement  is  charged 
to  the  work  accomplished,  a  large  amount  of  work  is  more  economically 
performed  than  a  small  amount,  since  that  portion  of  the  energy 
requirement  which  might  be  regarded  as  a  general  or  fixed  chargells 
distributed  over  a  larger  return  in  the  work  accomplished. 

RESPIRATORY  QUOTIENT  DURING  GRADE  WALKING. 

The  effect  upon  the  respiratory  quotient  of  varying  amounts  of 
work  in  grade  walking  may  be  seen  from  the  data  in  tables  52  to  55 
and  in  table  56.  The  obvious  effect  of  work  is  to  increase  both  the 
carbon  dioxide  produced  and  the  oxygen  consumed,  with  an  accom- 
panying increase  in  the  pulmonary  ventilation.  If  the  increased  ven- 
tilation of  the  lungs  causes  a  sudden  sweeping  out  of  the  preformed 
carbon  dioxide  in  the  blood  before  equilibrium  with  the  oxygen  demands 
can  be  met,  the  respiratory  quotient  is  increased,  or  if  the  character 
of  the  metabolism  is  changed  whereby  the  energy  will  be  supplied 
from  the  carbohydrate  store  of  the  body  rather  than  from  the  fat, 
the  result  will  be  an  increase  in  the  respiratory  quotient. 


R.Q. 
1.00 
95 
90 
85 
.80 
75 

0 

. 

« 

x 

_ 

' 

o 

K 

0 

X             ) 

*•• 

• 

« 

* 

«C 

°  to 

0    rf>  ' 

CD 

B 
0 

0 

X** 

MKOB 

V     Ml 

,«    ? 

ra  o 

„        ° 

,* 

wx-o 

EJXB/-a 

00 

Kg.ms. 


200 


400 


600 


800 


1200 


1400 


1600 


FIG.  20. — Respiratory  quotients  of  W.  K.  and  E.  D.  B.  referred  to 
kilogrammeters  of  work  performed  in  grade  walking.  (Val- 
ues per  minute  from  table  56.) 

The  respiratory  quotient  of  the  normal  subject  in  the  post-absorp- 
tive condition  is  not  far  from  0.82  to  0.85,  and  from  our  measurements 
of  the  transition  requirements  (see  p.  296),  it  would  appear  that  the 
oxygen  consumption  and  ventilation  reached  cons  tancyl  within  2|or 
3  minutes  after  the  change  from  rest  to  work.  As  the  subject  walked 
5  to  10  or  more  minutes  previous  to  each  period,  it  is  therefore  believed 
that  before  the  period  began  the  carbon  dioxide  and  oxygen  had 
become  constant  at  the  rate  demanded  by  the  work,  and  that  the 
respiratory  quotient  would  be  of  the  average  normal  value  unless  an 
alteration  in  the  character  of  the  metabolism  bad  taken  place. 

It  is  seen  in  table  56  (p.  221)  that  the  average  respiratory  quotient 
for  the  different  subjects  was  not  different  from  the  normal  standing 
average  for  the  lower  grades  and  speeds,  0.87  being  the  highest  average 
value  found  for  any  of  the  subjects  below  a  10  per  cent  grade  at  60^to 


METABOLISM   WITH    GRADE   WALKING. 


231 


65  meters  per  minute  (about  2.5  miles  an  hour).  It  may  also  be  seen 
that  the  respiratory  quotient  tended  to  increase  as  the  grade  and  speed 
increased.  This  is  more  apparent  in  figure  20,  in  which  the  respiratory 
quotients  for  W.  K.  and  E.  D.  B.  given  in  table  56  have  been  plotted 
for  experiments  with  varying  degrees  of  work.  In  this  chart  the 
majority  of  the  respiratory  quotients  up  to  approximately  600  kg.  m. 
of  work  fall  within  the  limits  of  0.80  to  0.87,  i.  e.,  the  normal  post- 
absorptive  respiratory  quotients,  and  for  700  to  1,000  kg.  m.  of  work, 
almost  half  of  the  respiratory  quotients  are  0.90  or  above,  while 
none  are  below  0.85.  For  more  than  1,100  kg.  m.  the  respiratory 
quotients  are  grouped  around  0.93  and  none  are  below  0.90,  while 
the  two  determinations  with  work  greater  than  1,300  kg.  m.  give  respi- 
ratory quotients  of  0.97.  Figure  20  gives  clear  indication  that  for 
such  short  periods  as  these,  600  kg.  m.  or  less  of  work  per  minute  do  not 
tend  to  alter  the  character  of  the  respiratory  quotient,  but  with  moder- 
ately heavy  to  heavy  work,  involving  over  600  kg.  m.  per  minute,  the 
body  alters  its  metabolism  by  a  tendency  to  a  selective  consumption  of 
its  carbohydrate  reserve. 

TABLE  60. — Comparison  of  respiratory  quotients  of  E.  D.  B.  during  grade  walking  for  the 
days  of  the  week  November  1  to  December  11,  1915,    (Subject  in  post-absorptive  condition.) 


Nov.  1  to  6. 

Nov.  8  to  13. 

Nov.  15  to  20. 

Nov.  22  to  27. 

Nov.29toDec.4. 

Dec.  6  to  11. 

Day. 

Work 

Respi- 

Work 

Respi- 

Work 

Respi- 

Work 

Respi- 

Work 

Respi- 

Work 

Respi- 

due to 

ratory 

due  to 

ratory 

due  to 

ratory 

due  to 

ratory 

due  to 

ratory 

due  to 

ratory 

grade- 

quo- 

grade- 

quo- 

grade- 

quo- 

grade- 

quo- 

grade- 

quo- 

grade- 

quo- 

lift. 

tient. 

lift. 

tient. 

lift. 

tient. 

lift. 

tient. 

lift. 

tient. 

lift. 

tient. 

kg.  m. 

kg.  m. 

kg.  m. 

kg.  m. 

kg.  m. 

kg.  m. 

Mon.  .  . 

143.5 

0.88 

155.0 

0.89 

222  A 

0.91 

250.5 

0.84 

387.7 

0.86 

346.6 

0.90 

Tues... 

120.2 

.83 

161.1 

.83 

215.4 

.82 

337.3 

.86 

464.4 

.87 

412.4 

.89 

Wed... 

124.7 

.83 

163.1 

.83 

289.9 

.84 

338.1 

.84 

474.4 

.89 

511.2 

.83 

Thurs 

140.7 

.82 

194.7 

.85 

0) 

403.5 

.91 

Fri 

124.1 

.82 

192.3 

.85 

395.9 

2.92 

418.9 

.89 

Sat  

141.8 

5.88 

217.5 

.85 

390.1 

4.88 

393.7 

.88 

thanksgiving  Day. 

2Rock  candy  in  supper  preceding  day. 


3Molasses  candy  in  supper  preceding  day. 
4Candy  and  nuts  in  supper  preceding  day. 


Zuntz  and  Schumburg1  and  Durig2  have  stated  that  work  pro- 
longed over  a  series  of  days  tends  to  reduce  the  carbohydrate  store  in 
the  body  with  a  simultaneous  lowering  of  the  respiratory  quotient  and 
that  a  rest  of  one  day  in  three  is  desirable  in  order  to  maintain  a  normal 
quotient.  Contrary  to  the  results  of  these  authors,  an  inspection  of 
the  respiratory  quotients  for  W.  K.  shows  no  evidence  of  a  tendency  for 
the  quotient  to  decrease  on  successive  days  of  walking  with  a  subse- 
quent increase  on  the  omission  of  an  experimental  day.  With  E.  D.  B. 


*Zuntz  and  Schumburg,  Physiologic  des  Marsches,  Berlin,  1901,  p.  258. 
2Durig,  Arch.  f.  d.  ges.  Physiol.,  1906,  113,  p.  263. 


232  METABOLISM   DURING   WALKING. 

the  quotients  in  the  first  few  weeks  of  the  series  (in  the  untrained 
period)  usually  show  higher  values  for  the  experiments  on  Mondays 
which  followed  the  day  of  rest  on  Sunday.  (See  table  60.)  Later  in 
the  study,  and  especially  when  the  work  became  more  intense,  this  is 
not  apparent,  for  the  later  quotients  follow  no  general  trend,  but  are  all 
on  a  higher  level  than  those  when  the  work  of  walking  was  lighter. 
With  this  subject  it  is  possible  that  during  the  intermission  on  Sunday 
there  was  an  accumulation  of  carbohydrate  in  the  body  which  was 
drawn  upon  during  the  walking  of  Monday,  thus  raising  the  quotient 
for  that  day.  If  this  were  the  case,  the  increase  in  the  body  carbo- 
hydrate appears  to  have  been  insufficient  to  supply  the  energy  re- 
quired to  keep  it  at  this  higher  level  on  the  following  days;  accordingly 
there  was  a  subsequent  return  of  the  quotient  to  the  previous  value. 
That  no  difference  in  the  Monday  quotients  is  apparent  when  the 
amount  of  walking  became  greater  may  be  explained  by  saying  that  the 
increase  in  the  metabolism  due  to  the  increase  in  the  work  may  have 
been  so  large  that  this  minor  factor  was  lost  sight  of.  Since  our  sub- 
jects were  uncontrolled  outside  of  the  Laboratory,  and,  aside  from  the 
data  regarding  the  last  meal  before  the  experiment,  no  detailed  record 
was  made  of  the  diet,  it  is  possible  that  the  higher  quotients  on  Monday 
have  no  special  significance  in  this  connection,  except  to  show  that 
some  change  in  diet  was  made  of  which  we  have  no  knowledge,  such  as 
a  possible  indulgence  in  candy  on  the  day  of  rest. 

The  absence  of  definite  evidence  in  our  results  of  the  influence  of  a 
day  of  rest,  as  compared  with  the  results  found  by  the  investigators 
referred  to,  may  be  due  to  a  difference  in  the  character  of  the  experi- 
ments. With  Zuntz  and  Schumburg  the  subject  was  carrying  a  load 
of  approximately  25  kg.1  while  walking  on  a  level  at  rates  from  70  to 
80  meters  per  minute.  This  does  not  allow  a  statement  in  terms  of 
kilogrammeters,  but  the  oxygen  consumption  was  no  greater  nor  as 
large,  in  many  instances,  as  found  for  the  subjects  W.  K.  and  E.  D.  B., 
who  were  walking  up-grade  without  a  load.  Then'  subjects  were  con- 
trolled in  their  diet,  while  ours,  as  stated,  were  unrestrained,  except 
for  a  12-hour  abstinence  from  food  preceding  the  experiment.  Evi- 
dently with  W.  K.,  and  possibly  with  E.  D.  B.,  the  work  performed  on 
these  days  was  not  such  as  to  reduce  the  store  of  body  carbohydrate 
to  so  great  an  extent  that  it  could  not  be  restored  to  a  normal  level 
during  the  resting  hours  of  the  remainder  of  the  day  and  night. 

After  the  writing  of  this  report  had  been  practically  completed,  the 
most  interesting  paper  of  Krogh  and  Lindhard,2  entitled  "The  relative 
value  of  fat  and  carbohydrate  as  sources  of  muscular  energy,  with 
appendices  on  the  correlation  between  standard  metabolism  and  the 
respiratory  quotient  during  resb  and  work,"  was  received.  The  experi- 

*Zuntz  and  Schumburg,  Physiologie  des  Marsches,  Berlin,  1901,  p.  249. 
*Krogh  and  Lindhard,  Biochem.  Journ.,  1920,  14,  p.  290. 


METABOLISM   WITH   GRADE   WALKING.  233 

ence  of  the  Nutrition  Laboratory  is  wholly  in  line  with  their  question- 
ing the  use  of  the  mouthpiece  in  researches  involving  specifically  a 
study  of  the  respiratory  quotient.  Benedict  and  Murschhauser1 
emphasized  the  desirability  of  studying  the  metabolism  during  muscu- 
lar work  in  a  respiration  chamber  "with  free  breathing,  without  the 
use  of  either  mouth  or  nose  appliances."  This  Krogh  and  Lindhard 
have  done  with  all  of  the  niceties  of  detail  characterizing  Krogh's  work. 
It  is  a  cause  for  regret  that  since  they  stress  especially  the  respiratory 
quotient  as  affected  by  muscular  work,  they  did  not  include  at  least  a 
few  experiments  with  an  oxygen  consumption  of  from  1,500  to  3,000 
c.  c.  per  minute,  as  it  was  especially  in  regard  to  these  periods  of  severe 
work  that  Benedict  and  Murschhauser  made  their  recommendations 
as  to  method  of  study.  Indeed,  the  results  given  in  this  present  re- 
port (see  table  56,  p.  221)  show  high  respiratory  quotients,  which,  in 
the  absence  of  demonstrated  technical  or  physiological  error,  lead  only 
to  the  conclusion  that  there  is  a  specific,  selective  carbohydrate  com- 
bustion with  this  intensity  of  performance. 

TOTAL  HEAT-OTJTPUT  DURING  GRADE  WALKING. 

The  total  heat  expended  per  minute  during  grade  walking  is  given 
in  tables  13  to  16,  and  also  in  column  j,  tables  52  to  55,  and  indicates 
the  range  of  requirements  for  men  of  different  weights  at  different 
grades  and  speeds.  As  the  amount  of  heat  produced  is  conditioned 
upon  the  work  accomplished  per  minute,  no  direct  comparison  can  be 
made  except  on  the  basis  of  kilogrammeters  of  work  performed.  These 
values,  computed  from  the  body-weight  and  grade-lift,  are  given  in 
column  /  of  tables  52  to  55. 

The  range  in  the  total  amounts  of  heat  developed  during  grade  walking 
is  limited  hi  the  case  of  the  two  subjects,  T.  H.  H.  and  H.  R.  R.,  as  they 
dropped  out  of  the  study  before  any  severe  amount  of  work  was  per- 
formed. The  range  for  W.  K.  is  from  3.72  to  10.57  calories,  with 
approximately  125  to  900  kg.  m.  of  work,  and  for  E.  D.  B.  from  2.59  to 
15.65  calories  for  work  ranging  from  59  to  1,569  kg.  m.  per  minute. 
This  last  value  is  the  average  of  two  periods  on  February  22,  when  the 
subject  walked  up  a  40  per  cent  grade  at  a  rate  of  65.2  meters  per 
minute  (2.50  miles  an  hour).  The  first  period  was  of  10  minutes  dura- 
tion, with  13  minutes  of  preliminary  walking.  At  the  close  of  the 
period,  the  subject  complained  of  pains  in  his  chest  and  was  doubtful 
of  his  ability  to  perform  a  second  period  of  similar  activity.  The  dura- 
tion of  the  last  period  was  reduced  to  6  minutes  after  a  preliminary 
walk  of  5  minutes,  as  the  subject  showed  signs  of  exhaustion. 

If  the  values  for  the  total  heat-output  per  minute  are  plotted  on  the  basis 
of  kilogrammeters  of  work,  as  is  done  in  figures  21  and  22,  it  is  seen  that 
the  total  heat-output  is  a  linear  function  of  the  work  performed  for  each 

Benedict  and  Murschhauser,  Carnegie  Inst.  Wash.  Pub.  No.  231,  1915,  p.  30. 


234 


METABOLISM   DURING   WALKING. 


grade.  It  appears  from  the  relative  positions  of  the  curves  for  W.  K. 
that  the  total  heat  produced  for  a  given  amount  of  work  is  somewhat 
higher  when  the  work  is  performed  at  a  fast  rate  of  walking  with  a  low 
grade.  For  instance,  with  400  kg.  m.  of  work  on  a  15  per  cent  grade, 
the  total  heat-output  would  be  5.62  calories,  while  with  the  same 


3  5 
kg.Tns! 300  500  700  ^00 

FIG.  21. — Total  heat-output  of  W.  K.,  referred  to  kilo- 
grammeters  of  work  performed  in  walking  on  dif- 
ferent grades.  (Values  per  minute.) 


15.5 
14.5 
13.5 
12.5 
11.5 
10.5 
9.5 
8.5 
7.5 
6.5 
5.5 
4.5 
3.5 

2.5 
Kg 

/ 

/ 

/ 

/  A 

/ 

/ 

^ 

y 

/ 

'% 

7 

// 

x> 

Y 

// 

'S 

™ 

A 

o 

/" 

/, 

•/• 

•-;.- 
[12 

1:1 

<v 

A 

/ 

z 

£ 

7 

$ 

/ 

r/° 
w 

/ 

ms.          200            400            600            800            1000           1200           1400           16 

FIG.  22. — Total  heat-output  of  E.  D.  B.,  referred  to  kilo- 
grammeters  of  work  performed  in  walking  on  dif- 
ferent grades.  (Values  per  minute.) 


METABOLISM   WITH   GRADE   WALKING. 


235 


amount  of  work  due  to  faster  walking  on  a  10  per  cent  grade  it  would 
be  6.08  calories.  This  characteristic  was  also  apparent  from  the  rela- 
tive positions  of  the  curves  for  the  total  carbon  dioxide  and  oxygen 
for  both  W.  K.  and  E.  D.  B.,  given  in  figures  16  to  19.  While  most 
of  the  curves  for  the  heat-output  of  E.  D.  B.  show  this  same  relation- 
ship between  the  heat  produced  for  a  definite  amount  of  kilogrammeters 
of  work  with  different  grades,  the  curve  for  th.3  35  per  cent  grade  and.'a 
part  of  the  curve  for  the  25  per  cent  grade,  as  well  as  the  two  points  for 
the  45  per  cent  grade,  indicate  a  higher  heat-output  than  is  found  for 
the  same  number  of  kilogrammeters  of  work  on  the  curve  for  the  next 
lower  grade.  These  exceptions  were  also  found  with  the  oxygen 
curves,  as  discussed  on  page  228. 

TABLE  61. — Minimum  and  maximum  heat-output  in  grade  walking 
during  experiments  without  food.     (Values  per  minute.) 


Subject. 

Minimum 
heat- 
output. 

Work  due 
to  grade- 
lift. 

Heat  per 
kg.  m.  of 
grade-lift. 

Maximum 
heat- 
output. 

Work  due 
to  grade- 
lift. 

Heat  per 
kg.  m.  of 
grade-lift. 

H.  R.  R  

cols. 
7  36 

kg.  m. 
475 

gm.-cals. 
15  5 

cats. 
9.95 

kg.  m. 
717 

gm.-cals. 
13.9 

T.  H.  H   

5  59 

328 

17  0 

6.39 

392 

16  3 

W.  K. 

3  72 

129 

28  8 

10  57 

891 

11  9 

E.  D.  B  

2.59 

59 

43.9 

15.65 

1,569 

10.0 

TABLE  02. — Comparison  for  E.  D.  B.  of  total  heat-output  per  kilogrammeter  of  work 
in  grade  walking  with  increasing  amounts  of  work.     (Values  per  minute.} 


Date. 

Work  due 
to  grade- 
lift. 

Total 
heat. 

Heat  per 
kg.  m.  of 
grade-lift. 

kg.  m. 

cats. 

gm.-cals. 

Apr.  15. 

59 

2.59 

43.9 

14. 

126 

3.14 

24.9 

8. 

223 

3.84 

17.2 

Mar.  24. 

310 

4.88 

15.7 

23. 

380 

5.39 

14.2 

Dec.  13. 

576 

6.92 

12.0 

Jan.     5  . 

993 

11.12 

11.2 

Feb.  11. 

1,250 

13.00 

10.4 

22. 

1,569 

15.65 

10.0 

The  minimum  and  maximum  daily  averages  for  the  total  heat-output 
of  H.  R.  R.,  T.  H.  H.,  W.  K.,  and  E.  D.  B.,  together  with  the  amount  of 
work  done  on  these  days,  are  given  in  table  61.  For  comparison,  the 
total  heat-output  per  kilogrammeter  of  vertical  grade-lift,  or  the  total 
energy  cost  for  1  kg.  m.  of  work  done  in  the  elevation  of  the  body,  has 
also  been  calculated  for  these  days  and  included  in  the  table.  As  the 


236 


METABOLISM   DURING   WALKING. 


basal  requirements  form  a  part  of  these  total  values,  the  cost  per  kilo- 
grammeter  of  work  is  naturally  larger  when  the  work  is  small  and  de- 
creases with  increasing  work.  This  is  clearly  seen  from  the  figures  col- 
lected in  table  62,  in  which  the  data  for  E.  D.  B.  for  increasing  amounts 
of  work  are  given  in  a  more  extended  form  than  in  table  61.  The  total 
heat  cost  per  kilogrammeter  is  here  shown  to  decrease  rapidly  at  first, 
with  increasing  amounts  of  work,  but  soon  reaches  a  limit;  above  1,000 
kg.  m.  the  total  cost  is  approximately  constant  at  10  gram-calories  per 
kilogrammeter  of  work  of  grade-lift.  The  fact  that  the  total  heat- 
output  per  kilogrammeter  of  work  accomplished  is  less  for  a  steep 
grade  and  slower  speed  than  for  a  low  grade  and  a  high  speed,  as  seen 
from  the  relative  positions  of  the  curves  in  figure  21  and  with  most  of 
the  curves  in  figure  22,  and  that  the  heat-output  per  kilogrammeter  is 
lowest  when  the  largest  amount  of  work  is  done  in  unit  time,  as  seen 
in  table  62,  may  explain  why  many  trained  walkers  prefer  a  short 
and  steep  ascent  to  a  more  circuitous  and  gradual  one. 

Curves  for  the  average  total  heat-output  of  W.  K.  and  E.  D.  B.  with 
different  amounts  of  work,  due  to  varying  grades  and  speeds,  are  in- 
cluded in  figures  23  and  24.  These  curves  are  based  upon  the  data  in 
table  56,  in  which  the  values  are  grouped  according  to  grade  and  rate  of 
walking.  The  curve  for  W.  K.  indicates  a  slight  tendency  to  deviate 
from  a  straight  line  at  the  lowest  point,  but  that  for  E.  D.  B.  is  linear 
throughout  its  entire  length  of  1,600  kg.  m.  If  we  estimate  the  basal 


C.C. 

2100 
1900 
1700   Cals. 

/ 

'/ 

^      ' 

t/ 

? 

1500    12.0 
1300    10.0 
1  100      8.0 
900      6.0 
700      4.0 

2.0 
1C 
Kg 

/ 

Y- 

^ 

£ 

. 

AS* 

/ 

I 

^ 

p" 

•>  c 

o-c 

a 
M.S. 

X 

^ 

X^ 

o 

0            300             500             700            90 

IDS. 

Fio.  23. — Total  oxygen  consumption  and  heat-produc- 
tion of  W.  K.,  referred  to  kilogrammeters  of  work 
performed  in  grade  walking.  (Values  per  minute 
from  table  56.) 


METABOLISM   WITH   GRADE   WALKING. 


237 


o, 


O.C. 

3100 
2900 
2700 
2500 
2300 
.2100 
1900 
1700 
1500 
1300 
1100 
900 
700 
500 

300 
Kg. 

^ 

Cals. 
16.0 
14.0 
12.0 
10.0 
8.0 
6.0 
4.0 

2.0 
30 

/ 

x 

^x 

' 

X 

X 

o»c 

ILS. 

• 

X 

/ 

5^ 

r       • 

-X 

^  " 

^ 

^ 

f 

/ 

• 

. 

5^% 

^" 

'/ 

. 

0^ 

^ 

x-"^ 

/• 

" 

^ 

v> 

^> 

^^ 

-r 

, 

X 

fiiT" 

J"1j> 

., 

^ 

*-** 

ms.          200             400             600             800            1000           1200           1400           16 

r\y.iit9.  f.\j\>  TW  \j\j-u  ww  iwv  iww  itw  luuvj 

FIG.  24. — Total  oxygen  consumption  and  heat-production  of  E.  D.  B., 
referred  to  kilogrammeters  of  work  performed  in  grade  walking.  (Val- 
ues per  minute  from  table  56.) 

requirement  of  E.  D.  B.,  as  was  done  in  considering  the  curve  for  the 
oxygen  consumption  given  in  the  same  figure  (see  p.  228),  we  find  his 
requirement  for  maintenance,  horizontal  component,  step-lift,  etc., 
to  be  2.00  calories,  and  superimposed  on  this  is  the  average  requirement 
of  8.7  gram-calories  for  each  kilogrammeter  of  work  due  to  grade-lift. 
Since  the  curve  for  W.  K.  is  not  linear  throughout,  no  definite  estimate 
can  be  made  for  his  basal  requirement,  but  the  slope  of  the  line  above 
400  kg.  m.  would  indicate  that  the  requirement  for  each  kilogrammeter 
of  work  due  to  grade-lift  was  10.5  gram-calories. 

The  total  heat-output  as  estimated  from  the  curves  in  figures  23 
and  24  for  increasing  amounts  of  work,  also  the  increase  over  the  stand- 
ing requirements  due  to  the  work  performed,  are  recorded  in  tables  63 
and  64.  It  is  seen  in  comparing  these  sets  of  figures,  as  was  done  with 
tables  58  and  59,  that  of  the  two  subjects  W.  K.  spent  the  larger  amount 
of  heat  over  the  standing  requirement  for  a  given  amount  of  work,  and 
also  that  the  heat  expended  per  unit  of  100  kg.  m.  in  excess  of  the 
standing  requirement  was  greater  for  small  than  for  large  amounts  of 
work.  In  both  cases  the  increment  in  the  heat  per  100  kg.  m.  decreased 
rapidly,  approximating  a  value  of  1.10  calories  for  W.  K.  and  0.96  cal- 
orie for  E.  D.  B.  for  800  to  900  kg.  m.,  while  for  1,500  to  1,600  kg.  m. 
the  value  for  E.  D.  B.  was  slightly  less,  i.  e.,  0.92  calorie. 


238 


METABOLISM   DURING  WALKING. 


TABLE  63. — Total  heat-output  of  W.  K.,  with  increasing  amounts  of  work,  in 
grade-walking  experiments  without  food,     (Values  per  minute.)1 


Increase  over  stand- 

Percentage increase 

ing  requirement. 

over  standing 

Kg.  m. 

of  work 

Heat- 

(1.10  cals.) 

requirement. 

done. 

output. 

Total 

Per  100 
kg.  m. 

Total. 

Per  100 
kg.  m. 

cals. 

cals. 

cals. 

p.  ct. 

p.  ct. 

100 

3.35 

2.25 

2.25 

205 

205 

200 

4.10 

3.00 

1.50 

273 

137 

300 

4.95 

3.85 

1.28 

350 

116 

400 

5.80 

4.70 

1.18 

427 

107 

500 

6.90 

5.80 

1.16 

527 

105 

600 

7.90 

6.80 

1.13 

618 

103 

700 

9.00 

7.90 

1.13 

718 

103 

800 

10.00 

8.90 

1.11 

809 

101 

900 

11.00 

9.90 

1.10 

900 

100 

Estimated  from  curve  in  figure  23. 

TABLE  64. — Total  heat-output  of  E.  D.  B.,  with  increasing  amounts  of  work,  in 
grade-walking  experiments  without  food.     (Values  per  minute.)1 


Increase  over  stand- 

Percentage increase 

ing  requirement. 

over  standing 

Kg.  m. 
of  work 

Heat- 

(1.16  cals.) 

requirement. 

done. 

output. 

Total 

Per  100 
kg.  m. 

Total. 

Per  100 
kg.  m. 

cals. 

cals. 

cals. 

p.  ct. 

p.  ct. 

100 

2.85 

1.69 

1.69 

146 

146 

200 

3.70 

2.54 

1.27 

219 

110 

300 

4.60 

3.44 

1.15 

297 

99 

400 

5.50 

4.34 

1.09 

374 

94 

500 

6.35 

5.19 

1.04 

447 

89 

600 

7.25 

6.09 

1.02 

525 

88 

700 

8.10 

6.94 

.99 

598 

85 

800 

8.95 

7.79 

.97 

672 

84 

900 

9.80 

8.64 

.96 

745 

83 

1,000 

10.70 

9.54 

.95 

822 

82 

1,100 

11.60 

10.44 

.95 

900 

82 

1,200 

12.45 

11.29 

.94 

973 

81 

1,300 

13.30 

12.14 

.93 

1,047 

80 

1,400 

14.20 

13.04 

.93 

1,124 

80 

1,500 

15.05 

13.89 

.93 

1,197 

80 

1,600 

15.90 

14.74 

.92 

1,271 

79 

Estimated  from  curve  in  figure  24. 
INCREMENT  IN  HEAT-OUTPUT  DUE  TO  GRADE-LIFT. 
TOTAL  INCREMENT  IN  HEAT  DUE  TO  GRADE-LIFT. 

That  portion  of  the  total  heat  expended  during  grade  walking  that 
is  due  to  the  grade  per  se  is  the  total  heat-output  less  the  energy  re- 
quirements for  standing  and  horizontal  walking.  This  difference  is 


METABOLISM   WITH   GRADE   WALKING. 


239 


Cals. 
13.0r 


Gala. 
8.0 


/- 


& 


-3^ 

iao 


7.0 
6.0 
5.0 
4.0 
3.0 
2.0 
1.0 

joL 

Kg.ms.  300  500  700  900 

FIG.  25. — Daily  increments  in  heat-production  over 
standing  requirement  and  horizontal  component, 
referred  to  kilogrammeters  of  work  done  in  walking 
experiments  on  different  grades  with  W.  K.  (Val- 
ues per  minute.) 


12.0. 
11.0. 
10.0. 

9.0. 

8.0. 

7.0. 

6.0. 

5.0. 

4.0. 

3.0. 

2.0. 

1.0. 


Kg.ms. 


200 


600 


800 


1000 


1200 


1400 


1600 


FIG.  26. — Daily  increments  in  heat-production  over  standing 
requirement  and  horizontal  component,  referred  to  kilo- 
grammeters of  work  done  in  walking  experiments  on  dif- 
ferent grades  with  E.  D.  B.  (Values  per  minute.) 


240 


METABOLISM   DURING   WALKING. 


recorded  in  column  o  of  tables  52  to  55.  The  standing  requirements  in 
tables  3  to  7  and  the  increments  due  to  walking  on  a  level  given  in 
tables  29  to  33  are  used  for  obtaining  the  total  requirements  for  these 
two  factors.  The  values  used  for  deduction  were  either  determined  on 
the  same  day  or  represent  an  average  value,  the  selections  being  noted 
in  the  footnotes  to  tables  52  to  55.  These  increments  in  the  heat-output 
which  are  due  specifically  to  the  grade  have  been  plotted  for  W.  K. 
and  E.  D.  B.  for  each  grade  on  the  basis  of  kilogrammeters  of  work. 
(See  figs.  25  and  26.)  It  is  seen  in  these  figures  that  the  heat  increment 
is  a  linear  function  of  the  work  done,  as  was  the  total  heat  (see  figs.  21 
and  22),  but  in  these  curves,  with  the  basal  and  horizontal  require- 
ments eliminated,  the  amounts  of  heat  produced  for  the  same  amounts 
of  work  with  different  grades  more  nearly  coincide  and  the  curves  as  a 
whole  make  a  more  nearly  uniform  and  continuous  grouping,  thus  indi- 
cating that  the  heat  increment  is  practically  independent  of  whether 
the  given  amount  of  work  is  produced  by  altering  the  rate  of  walking 
or  the  grade. 


4 


FIG.  27. — Average  increments  in  heat-production  due  to  grade- 
lift  in  walking  experiments  with  E.  D.  B.  (Values  per  min- 
ute from  table  56.) 

To  show  the  relation  between  the  increment  in  the  heat-output  and 
the  grade  and  speed  used  in  walking,  the  data  for  E.  D.  B.  in  table  56 
have  been  plotted  for  the  various  speeds  and  grades  and  the  curves 
given  in  figure  27.  It  will  be  seen  from  these  curves  that  a  change  in 
speed  from  35-40  meters  to  75-80  meters  per  minute  (or  approximately 
1.5  to  3  miles  per  hour)  on  a  20  per  cent  grade  increased  the  heat-output 
due  to  the  grade  walking  approximately  4.5  calories,  while  a  change 
from  a  5  per  cent  grade  to  a  20  per  cent  grade  increased  this  factor 


METABOLISM   WITH   GRADE   WALKING. 


241 


about  2.25  calories  when  E.  D.  B.  walked  at  35  to  40  meters  per  minute, 
and  about  6.25  calories  when  he  walked  at  75  to  80  meters  per  minute. 
These  changes  may  be  calculated  on  a  percentage  basis  by  referring 
to  the  values  in  column  m  of  table  56  (p.  221).  Thus,  a  change  in  speed 
from  35^10  meters  per  minute  to  75-80  meters  per  minute  increased  the 
heat-output  over  that  requited  for  standing  and  the  horizontal  com- 
ponent 0.42  calorie,  or  60  per  cent,  with  a  5  per  cent  grade;  1.76  calo- 
ries, or  108  per  cent,  with  a  10  per  cent  grade;  2.29  calories,  or  92  per 
cent,  with  a  15  per  cent  grade;  and  4.30  calories,  or  139  per  cent, 
with  a  20  per  cent  grade.  When  the  subject  was  walking  with  a  speed 
of  35  to  40  meters  and  on  a  5  per  cent  grade,  the  heat-output  due  to 
grade  walking  averaged  0.70  calorie.  When  he  changed  to  a  grade  of 
10  per  cent  without  change  of  speed,  the  heat-output  increased  0.93 
calorie,  or  133  per  cent;  with  a  15  per  cent  grade,  the  increase  over  the 
5  per  cent  value  was  1.8  calories,  or  257  per  cent;  and  with  a  20  per 
cent  grade,  2.39  calories,  or  341  per  cent.  Similarly,  when  the  speed  of 
walking  was  75  to  80  meters  per  minute,  the  percentage  increases  over 
the  5  per  cent  grade  were  203  per  cent  for  the  10  per  cent  grade,  328  per 
cent  for  the  15  per  cent  grade,  560  per  cent  for  the  20  per  cent  grade, 
and  729  per  cent  for  the  25  per  cent  grade. 

INCREMENT  IN  HEAT  PER  KILOGRAMMETER  OP  WORK  DONE  IN  GRADE-LIFT. 

From  the  increment  in  the  heat-output  due  to  the  grade  and  the 
total  kilogrammeters  of  work  due  to  the  grade-lift,  the  heat  outlay  per 
kilogrammeter  of  work  done  in  the  elevation  of  the  body  has  been 
computed  and  recorded  hi  column  p  of  tables  52  to  55.  A  summary 
of  the  daily  averages  is  given  in  table  65.  A.  J.  0.,  with  only  one 

TABLE  65. — Average  increment  in  heat-output  due  to  grade-lift  per 
kilogrammeter  of  work. 


No.  of 

Minimum 

Maximum 

Average 

Subject. 

experi- 

incre- 

incre- 

incre- 

ments. 

ment. 

ment. 

ment. 

gm.-cals. 

gm.-cals. 

gm.-cals. 

A.  J.  O.  .  . 

1 

5.6 

H.  R.  R.. 

6 

7.2 

8.0 

7.5 

T.  H.  H.. 

8 

6.8 

8.1 

7.6 

W.  K  

48 

5.3 

9.3 

8.1 

E.  D.  B... 

79 

4.8 

8.7 

7.0 

Average  . 

6.0 

8.5 

7.2 

experiment  of  two  periods,  shows  the  lowest  average  value,  or  5.6 
gram-calories.  This  was  for  the  low  grade  of  3.6  per  cent,  with  but 
172  kg.  m.  of  work.  The  total  heat-output  was  correspondingly  low 
and  the  proportionate  probability  of  error  on  deducting  the  values  for 
the  standing  and  horizontal  walking  requirements  was  naturally  large. 


242  METABOLISM   DURING  WALKING. 

The  values  for  H.  R.  R.  were  fairly  uniform,  averaging  7.5  gram- 
calories,  with  a  range  in  work  performed  of  452  to  717  kg.  m.  The 
highest  value  of  8.0  gram-calories  was  in  the  one  experiment  with  a 
15  per  cent  grade.  T.  H.  H.  also  performed  his  task  at  an  average 
energy  cost  of  7.6  gram-calories,  although  his  daily  work  did  not 
exceed  392  kg.  m.  as  compared  with  717  kg.  m.  for  H.  R.  R. 

W.  K.  on  his  first  day,  with  a  3.6  per  cent  grade,  did  only  131  kg.  m. 
of  work,  and  his  low  heat  cost  for  this  work  of  5.3  gram-calories  may  be 
assumed  as  due  largely  to  the  difficulty  of  measuring  the  heat  differ- 
ences in  these  small  amounts.  His  maximum  cost  was  9.3  gram-calo- 
ries when  719  kg.  m.  of  work  were  done  and  the  average  value  8.1 
gram-calories. 

With  E.  D.  B.  the  range  was  wider  than  for  any  of  the  five  men.  His 
lowest  daily  cost  per  kilogrammeter  was  4.8  gram-calories,  and  a  closely 
approximate  value  was  found  on  several  other  days.  Although  these 
low  values  are  not  necessarily  for  the  period  of  the  least  amount  of 
work,  in  all  but  one  case  the  work  performed  was  below  200  kg.  m.  and 
the  heat  due  to  the  grade  work  as  computed  constitutes  approximately 
but  one-fourth  of  the  total  heat  measured.  These  low  values  appear 
both  in  the  early  period  of  grade  walking  and  again  on  the  last  day, 
when  a  2.5  per  cent  grade  was  walked,  with  an  outlay  of  59  kg.  m.  It 
seems  probable,  therefore,  that  the  low  increment  in  the  heat-output 
per  kilogrammeter  found  with  A.  J.  0.,  W.  K.,  and  E.  D.  B.  is  due  to 
the  method  of  apportioning  the  heat  for  standing  and  horizontal 
walking  requirements,  rather  than  to  the  fact  that  the  values  were 
actually  low.  The  average  increment  due  to  grade-lift  for  E.  D.  B.  was 
7.0  gram-calories,  and  for  the  group  of  five  subjects,  7.2  gram-calories. 
Omitting  A.  J.  0.  from  the  average,  since  he  had  but  one  experiment, 
the  average  value  for  the  four  remaining  subjects  is  7.6  gram-calories 
per  kilogrammeter  of  work  done. 

In  the  discussion  of  the  results  of  the  horizontal- walking  experiments, 
it  was  seen  that  some  evidence  of  a  training  effect  appeared  in  the  later 
experiments  with  E.  D.  B.  (See  tables  34  and  43,  pp.  141  and  159.) 
The  data  obtained  in  the  experiments  on  grade  walking  do  not  offer 
so  great  an  opportunity  for  a  study  of  the  effect  of  training  upon  the 
oxygen  consumption  and  the  heat-production  with  a  definite  amount  of 
work  as  might  be  expected,  owing  to  the  difference  in  the  conditions  of 
the  experiments  and  to  the  more  or  less  progressive  increase  in  work  as 
the  research  continued.  This  increase  in  work  was  due  to  the  fact 
that  hi  the  earlier  experiments  the  lower  grades  were  used  when  the 
subject  was  less  practiced  in  walking,  and  as  the  series  progressed  the 
grades  were  gradually  increased,  so  that  in  the  later  experiments  the 
higher  grades  were  used  when  the  subject  may  be  said  to  have  been 
trained  in  walking.  Near  the  close  of  E.  D.  B.'s  five  months  of  service 
as  a  subject,  low  grades  were  again  used  in  a  few  experiments,  and 


STEP-LIFT   IN   GRADE   WALKING.  243 

these  are  the  only  results  which  are  at  all  comparable  with  data 
obtained  in  the  earlier  part  of  the  series,  when  the  subject  was  un- 
trained. These  low-grade  experiments  were,  however,  so  few  in  num- 
ber and,  particularly,  the  total  amount  of  work  was  so  small,  being 
in  all  cases  under  300  kg.  m.  per  minute,  that  the  data  do  not  lend  them- 
selves to  the  critical  discussion  of  the  effect  of  training  upon  the  energy 
cost  per  kilogrammeter  of  work  done  in  walking  up-grade. 

STEP-LIFT  DURING  GRADE  WALKING. 

The  measurement  of  the  step-lift  during  horizontal  walking  is  com- 
paratively simple  as  determined  by  the  revolution  of  the  work-adder 
wheel,  supplemented  and  controlled  at  tunes  by  the  kymograph  tracings 
of  the  spring  pointer  of  Dr.  C.  Tigerstedt.1  (See  p.  30.)  The  results 
of  these  measurements  have  been  discussed  in  an  earlier  section.  (See 
p.  155.) 

An  attempt  was  made  to  measure  the  step-lift  in  grade  walking  by 
the  method  used  in  the  horizontal-walking  experiments.  There  is, 
however,  a  decidedly  different  type  of  step-lift  in  grade  walking  as 
compared  to  that  in  walking  on  a  level,  for  in  grade  walking  the  weight 
is  of  necessity  thrown  more  on  the  toes  than  in  walking  on  a  horizontal 
plane  and  the  center  of  gravity  must  be  farther  forward.  In  the  grade- 
walking  experiments  the  body  continually  moved  up  an  inclined  plane 
(the  treadmill  belt),  which,  to  be  sure,  was  continually  passing  by  the 
body  of  the  subject.  Was  any  of  the  movement  recorded  as  step-lift 
actually  due  to  the  "grade-lift"  of  the  body,  or  was  the  record  an  un- 
contaminated  measure  of  the  particular  type  of  step-lift  necessarily 
accompanying  grade  walking?  It  was  considered  that  the  position 
of  the  subject  on  the  treadmill  was  §o  closely  determined  by  the  mouth- 
piece and  the  fork  of  the  step-lift  recorder  which  rested  on  his  shoulder 
(see  fig.  1,  p.  19)  that  he  could  alter  his  relative  position  on  the  tread- 
mill but  little.  This  supposition  has  been  confirmed  by  the  photo- 
graphic tests  previously  described  on  page  31.  It  is  recognized,  how- 
ever, that  possibilities  of  error  in  these  measurements  are  present, 
as  was  the  case  with  the  measurements  for  walking  on  a  level. 

As  pointed  out  in  the  description  of  the  technique  (p.  33),  the  manner 
of  measuring  the  step-lift  in  these  experiments  is  fairly  open  to  criti- 
cism as  to  the  position  of  the  fork.  (See  fig.  1,  p.  19.)  After  the 
preparation  of  this  manuscript  was  nearly  completed,  it  seemed 
desirable  to  make  tests  to  note  the  influence,  if  any,  of  a  change  in 
position  of  the  fork  with  relation  to  the  plane  upon  which  the  subject 
walks.2  Consequently,  the  mill  was  set  at  a  30  per  cent  grade  and  the 
fork  was  placed  in  a  position  parallel  to  the  belt  of  the  mill.  Under 

'C.  Tigerstedt,  Skand.  Arch.  f.  Physiol.,  1913,  30,  p.  299. 

2The  author  wishes  to  acknowledge  his  indebtedness  to  Dr.  F.  G.  Benedict,  who  carried  out 
these  experiments  at  a  time  when  he  himself  was  unable  to  co-operate. 


244  METABOLISM   DURING   WALKING. 

these  conditions  the  cord  attached  to  the  fork  and  leading  to  the  kymo- 
graph passed  upwards  hi  a  direction  perpendicular  to  the  plane  of  the 
mill  to  a  pulley  above,  thence  to  a  second  pulley,  and  thence  to  the 
kymograph. 

Unfortunately,  none  of  the  original  subjects  in  this  research  could  be 
secured  for  the  later  tests,  as  they  were  no  longer  in  the  vicinity  of 
Boston.  Consequently,  another  subject  was  used,  and  tests  were  made 
with  the  fork  not  only  hi  the  new  position,  but  also  for  comparison  in 
the  position  used  in  the  research.  No  measurements  of  the  metabolism 
accompanied  these  tests.  Two  speeds  of  walking  were  employed,  one 
approximately  50  to  55  meters  per  minute  and  another  from  75  to  87 
meters  per  minute.  The  results  show  that  when  the  fork  was  parallel 
to  the  treadmill  belt  there  was,  as  a  matter  of  fact,  a  somewhat  greater 
step-lift  than  when  the  fork  was  left  in  the  original  position.  (See 

%  1.) 

The  string  was  then  attached  at  the  belt  of  the  subject  in  the  position 
originally  used  by  Benedict  and  Murschhauser1  and  the  results  com- 
pared with  those  obtained  with  the  fork  parallel  to  the  treadmill  belt. 
Very  satisfactory  agreement  was  obtained  in  all  cases.  The  important 
point  brought  out  in  this  test  is  that  the  step-lift  as  measured  by  the 
method  employed  in  the  entire  research  reported  in  this  publication, 
namely,  with  the  fork  parallel  to  the  floor  and  not  to  the  angle  of  ascent, 
is  in  all  probability  somewhat  too  small  rather  than  too  large.  In  the 
absence  of  the  original  subjects,  particularly  E.  D.  B.,  it  seemed  unde- 
sirable to  make  an  attempt  to  establish  closely  related  correction  fac- 
tors by  comparing  the  step-lift  during  grade  walking  as  measured  with 
the  probable  step-lift  measured  with  the  fork  in  what  we  now  believe 
to  be  the  proper  position,  i.  e.,  parallel  to  the  surface  of  the  treadmill. 

The  method  of  studying  the  locomotion  of  ihan,  devised  by  Braune 
and  Fischer,2  is  extraordinarily  ingenious.  No  one  who  reads  their 
original  memoir  and  the  subsequent  analyses  by  Fischer  can  fail  to  be 
impressed  by  this  profitable  method  of  attack.  It  is  particularly  un- 
fortunate for  us  that,  if  experiments  were  made  by  these  authors  on 
grade  walking,  no  photographic  results  were  given  and  no  data  pub- 
lished. Had  this  been  the  case,  we  feel  sure  that  the  element  of  un- 
certainty as  to  the  step-lift  in  grade  walking  would  have  been  quickly 
dispelled. 

Apparently  from  purely  theoretical  considerations,  Amar3  has 
sketched  the  hypothetical  movements  of  the  body  in  grade  walking 
and  clearly  indicates  a  somewhat  higher  oscillatory  motion  perpen- 
dicular to  the  plane  of  the  belt  than  would  obtain  in  horizontal  walking. 

'Benedict  and  Murschhauser,  Carnegie  Inst.  Wash.  Pub.  No.  231,  1915,  pp.  32  and  40. 
JBraune  and  Fischer,  Abhandl.  d.  math.-phys.  Klasse  d.  Konigl.  Sschsischen  Gesellsch.  d. 
Wissensch.,  Leipsic,  1895,  21,  p.  153. 

3Amar,  Le  moteur  humain,  Paris,  1914,  p.  476. 


STEP-LIFT   IN   GRADE   WALKING. 


245 


Step-lift  per  minute. — In  considering  the  step-lift  per  minute,  recorded 
in  column  g  of  tables  52  to  55,  it  is  seen  that  although  the  variations 
present  in  horizontal  walking  between  experimental  periods  with  like 
conditions  are  likewise  to  be  found  here,  the  amount  of  lift  per  minute 
increased  in  approximate  conformity  with  the  speed  for  the  same  grade. 
It  may  also  be  noted  that  the  lift  per  minute  for  the  same  or  approxi- 
mately the  same  speed  increased  with  the  grade,  and  that  the  total  lift 
reached  a  very  appreciable  amount  at  the  higher  grades  and  speeds. 
Thus,  E.  D.  B.  had  a  total  step-lift  per  minute  of  7.1  meters  when 
walking  on  a  30  per  cent  grade  at  69.5  meters  per  minute  and  on  a  40 
per  cent  grade  at  65  meters  per  minute,  as  compared  with  a  total  step- 
lift  per  minute  of  1.7  meters  on  a  5  per  cent  grade  at  65.4  meters  per 
minute.  (See  table  55,  p.  209.) 

Step-lift  per  step. — The  lift  per  step  likewise  shows  an  increase  with 
the  higher  grades  and  speeds.  W.  K.,  on  March  4,  walking  on  a  3.6  per 
cent  grade  at  69  meters  and  114  steps  per  minute,  had  a  lift  per  step  of 

TABLE  66. — Average  step-lift  per  step  of  E.  D.  B.  in  grade  walking  for  approximately 
the  same  speeds  but  with  varying  grades.     (Values  per  minute.) 


Step-lift  per  step  at  speed  of  — 

Per  cent 

grade. 

Less  than 

60  to  70 

70  to  80 

60  meters. 

meters. 

meters. 

cm. 

cm. 

cm. 

0 

1.18 

2.05 

2.53 

5 

1.36 

1.85 

2.63 

10 

2.50 

3.68 

4.06 

15 

3.13 

3.95 

4.78 

20 

4.04 

4.98 

4.69 

25 

4.61 

5.68 

6.36 

30 

5.38 

5.94 

35 

5.43 

6.57 

40 

6  18 

6.88 

45 

5.84 

1.2  cm.,  while  on  June  17,  on  a  25  per  cent  grade  at  67  meters  and  120 
steps  per  minute,  it  was  4.6  cm.  (See  tables  15  and  54,  pp.  71  and  199.) 
A  summary  of  the  data  obtained  for  the  lift  per  step  of  E.  D.  B.  during 
grade  walking  is  given  in  table  66,  grouped  according  to  grade  and 
speed.  The  values  for  horizontal  walking  (0  per  cent  grade)  are 
also  given  for  comparison.  The  lift  per  step  for  E.  D.  B.  with  a  5  per 
cent  grade  and  a  speed  below  60  meters  per  minute  was  1.36  cm.,  only 
slightly  greater  than  the  average  found  during  horizontal  walking 
(1.18  cm.)  for  approximately  the  same  speed.  For  the  highest  grades 
and  speeds,  however,  the  lift  per  step  was  between  6  and  7  cm. 


246 


METABOLISM   DURING   WALKING. 


COMPARISON  OF  STEP-LIFT  IN  HORIZONTAL  AND  GRADE  WALKING. 
Although  the  data  for  the  step-lift  as  measured  may  be  found  scat- 
tered throughout  the  tables,  it  seems  desirable  to  make  a  direct  com- 
parison of  the  step-lift  in  horizontal  walking  with  the  step-lift  in  grade 
walking  as  measured  by  the  apparatus  pictured  in  figure  1.  Such 
comparison  should,  however,  be  subject  to  the  criticism  and  at  least 
theoretical  corrections  brought  out  in  the  discussion  of  the  technique 
on  page  31.  Using  the  data  for  our  most  frequently  employed  sub- 
ject, E.  D.  B.,  we  have  collected  in  table  67  a  series  of  values  comparing 
the  step-lift  of  this  subject  during  horizontal  and  grade  walking  at  an 

TABLE  67. — Comparison  of  step-lift  of  E.  D.  B.  in  horizontal  and  grade  walking 
at  an  approximate  speed  of  1+5  meters.     (Values  per  minute.) 


Date  and 
conditions. 

Grade. 

Distance 
walked. 

No.  of 

steps. 

Length 
of  step. 

Step- 
lift. 

Step-lift 
per  step. 

1915. 
Horizontal  walking: 
Oct    30 

p.  ct. 

meters. 
43.9 

80.3 

cm. 

54.7 

meters. 
0.66 

cm. 
0.82 

Nov     1 

44.3 

79.7 

55.6 

.72 

.90 

2  

43.2 

79.9 

54.1 

.70 

.88 

3  

44.5 

85.3 

52.2 

.76 

.89 

5  

46.2 

81.9 

56.4 

.81 

.99 

6     

45.9 

80.8 

56.8 

.75 

.93 

10     

47.8 

84.7 

56.4 

1.00 

1.18 

17         

45.7 

79.0 

57.8 

.78 

.99 

22         

47.4 

80.7 

58.7 

.79 

.98 

Dec      4         ... 

46.7 

79.0 

59.1 

.93 

1  18 

6         .    . 

45.0 

78.5 

57.3 

.68 

.87 

7  

45.8 

77.1 

59.4 

.67 

.87 

Grade  walking: 
Nov     4     

5.0 

48.2 

79.9 

60.3 

0.99 

1.24 

6         

5.0 

48.2 

79.5 

60.6 

1.00 

1  26 

17  

10.3 

48.0 

81.1 

59.2 

1.86 

2.29 

Dec.     7  

15.0 

46.4 

81.3 

57.1 

2.42 

2.98 

1916. 
Feb.     2     

25.0 

46.5 

85.9 

54.1 

4.31 

5  02 

8  

30.0 

46.0 

88.8 

51.8 

4.60 

5.18 

18  

40.0 

49.5 

89.9 

55.1 

5.64 

6  27 

average  speed  of  45  meters.  The  different  grades  used  in  the  grade- 
walking  experiments  are  also  indicated.  The  first  half  of  the  table 
consists  simply  of  a  repetition  of  horizontal  walking  on  different  days, 
and  consequently  shows  no  great  variation.  As  a  matter  of  fact,  the 
total  step-lift  ranged  from  0.66  to  1.00  meter  per  minute  on  the  days 
selected  for  comparison,  and  the  step-lift  per  step  from  0.82  to  1.18  cm. 
Since  all  of  the  horizontal-walking  data  are  not  here  included,  it  seems 
unnecessary  to  assume  an  average,  and  it  will  not  be  used  in  the  sub- 
sequent discussion. 

The  values  for  the  grade  walking  are  given  in  the  lower  part  of  the 
table.  It  will  be  noted  that  the  distance  walked  per  minute  was 
slightly  higher  in  most  instances  than  in  the  horizontal  walking.  Not- 


STEP-LIFT   IN   GRADE   WALKING. 


247 


withstanding  the  somewhat  greater  speed  in  grade  walking,  the  num- 
ber of  steps  was  not,  as  a  rule,  larger  than  in  horizontal  walking  until 
a  grade  of  25  per  cent  was  reached;  thereafter  the  number  of  steps 
taken  per  minute  was  larger.  The  step-lift  increased  very  perceptibly 
with  the  grade  and  likewise  the  step-lift  per  step. 

In  table  68  a  similar  comparison  is  made  when  the  average  speed  for 
both  horizontal  and  grade  walking  was  77  meters  per  minute.  In  the 
upper  part  of  the  table  the  data  for  horizontal  walking  are  more  or  less 
representative  of  duplicate  experiments  on  different  days  and  show  no 
great  variation.  During  the  grade  walking  there  was,  as  with  the 
slower  speed,  a  very  perceptible  increase  in  the  number  of  steps  with 
the  higher  grades,  beginning  at  20  per  cent,  although  it  is  again  to  be 
noted  that  in  three  of  the  four  tests  in  grade  walking  the  actual  rate  of 
walking  per  minute  was  somewhat  higher  than  during  the  horizontal 
walking.  The  step-lift  increased  pronouncedly,  as  did  the  step-lift 
per  step. 

TABLE  68. — Comparison  of  step-lift  of  E.  D.  B.  in  horizontal  and  grade  walking 
at  an  approximate  speed  of  77  meters.     (Values  per  minute.) 


Date  and 
conditions. 

Grade. 

Distance 
walked. 

No.  of 
steps. 

Length 
of  step. 

Step- 
lift. 

Step-lift 
per  step. 

1915 
Horizontal  walking: 
Oct.  27  

p.  ct. 

meters. 
77.7 

104.5 

cm. 
74.4 

meters. 
2.91 

cm. 

2.78 

28  

77.8 

106.5 

73.1 

2.78 

2.61 

29  

78.0 

104.8 

74.4 

2.95 

2.81 

Nov.  13  

76.7 

103.9 

73.8 

2.75 

2.65 

15  

77.0 

104.0 

74.0 

2.83 

2.72 

16  

76.9 

103.7 

74.2 

2.90 

2.80 

19  

77.9 

104.1 

74.8 

2.43 

2.33 

Dec.     1  

76.2 

105.3 

72.4 

2.72 

2.58 

Grade  walking: 
Nov.  30  

10 

78.5 

101.7 

77.2 

4.05 

3.98 

Dec.  16  

15 

81.3 

107.1 

75.9 

5.17 

4.83 

31  

20 

80.1 

110.2 

72.7 

4.69 

4.26 

1916. 
Feb.     7  

25 

75.9 

109.3 

69.4 

6.95 

6.36 

It  was  a  special  consideration  of  these  latter  factors,  namely,  the  step- 
lift  and  the  step-lift  per  step,  that  led  us  to  surmise  that  the  method  of 
measurement  of  the  step-lift  indicated  in  figure  1,  i.  e.,  with  the  fork 
parallel  to  the  floor  and  not  parallel  to  the  plane  of  walking,  might 
incorporate  in  the  graphic  record  a  certain  component  that  should 
properly  be  ascribed  to  the  grade-lift.  This  surmise  led  to  the  series 
of  experiments  reported  on  page  243,  from  which  the  conclusion  is  drawn 
from  tests  made  on  a  single  subject  (unfortunately  not  one  of  the 
original  group)  that  the  step-lift  as  measured  was  probably  not  con- 
taminated by  grade-lift,  but,  if  anything,  with  the  fork  parallel  to  the 
floor,  the  apparatus  does  not  record  so  large  oscillations  of  the  shoulders 


248  METABOLISM   DURING   WALKING. 

in  a  direction  perpendicular  to  the  inclined  plane  of  the  belt  as  it  does 
when  the  fork  is  parallel  to  the  belt.  It  is  assumed,  therefore,  in  sub- 
sequent discussion,  that  the  step-lift  as  actually  measured  and  re- 
corded in  this  publication  is  not  far  from  correct,  though  probably 
somewhat  below  rather  than  above  the  true  value. 

WORK  OF  ASCENT. 

In  addition  to  the  work  which  the  subject  performed  of  lifting  the 
body-weight  to  the  elevation  produced  by  the  grade  of  the  treadmill, 
ordinarily  considered  as  the  only  positive  work  done  in  grade  walking, 
we  must  also  take  into  account  the  work  which  was  done  (theoretically, 
at  least)  in  lifting  the  body  a  few  centimeters  at  each  step  in  the  rise 
and  fall  of  the  body  due  to  the  step-lift.  That  the  work  of  grade-lift 
is  positive  and,  in  the  transportation  of  a  superimposed  load  up  a  road, 
may  be  of  economic  significance,  must  not  obliterate  the  fact  that 
physiologically,  if  the  body,  or  indeed  a  superimposed  load,  is  lifted  a 
few  centimeters  during  each  step,  positive  work  is  being  accomplished, 
uneconomical  though  it  may  be.  The  sum  of  the  work  due  to  the  step- 
lift  and  that  due  to  the  grade-lift  represents  what  may  therefore  be 
designated  as  the  "work  of  ascent."  From  the  step-lift  as  actually 
measured  and  the  weight  of  the  body,  the  work  performed  as  a  result 
of  the  step-lift  has  been  computed  and  is  recorded  in  column  h  of  tables 
52  to  55.  The  "work  of  ascent"  is  given  in  column  i  of  the  same  tables. 

In  considering  the  work  done  during  grade  walking,  we  may  see  from 
previous  discussion  that,  owing  to  the  uncertainty  as  to  the  actual 
amount  of  work  due  to  the  step-lift,  the  exact  apportionment  of  the 
total  work  between  that  due  to  the  elevation  of  the  body  in  the  grade- 
lift  and  that  due  to  the  step-lift  is  difficult.  Doubtless  a  more  subtle 
analysis  of  the  mechanics  of  locomotion  in  the  line  of  the  particularly 
ingenious  method  of  Braune  and  Fischer,1  possibly,  by  means  of 
specially  illuminated  and  figured  backgrounds,  and  the  ultra-rapid 
motion-picture  camera,  may  clarify  the  situation.  Since  this  may 
not  be  made  at  the  present  time,  and  it  is  desirable  to  present  a  hitherto 
neglected  factor  in  the  computation  of  the  efficiency  of  the  body  in 
grade  walking,  we  have  assumed  that,  as  a  result  of  the  experiments 
carried  out  as  this  report  was  being  written  and  the  considerations 
set  forth  on  pages  243  to  244,  the  measurements  of  the  step-lift  obtained 
in  this  research  during  grade  walking  included  none  of  the  elevation 
due  to  the  grade-lift  component,  and  they  thus  represent  the  true 
step-lift.  The  computations  of  the  work  due  to  this  factor  which 
have  been  made  from  them  may  thus  be  considered  as  giving  the  true 
results. 

1Braune  and  Fischer,  Abhandl.  d.  math.-phys.  Klasse  d.  Konigl.  Sachsischen  Gesellsch.  d. 
Wissensch.,  Leipsic,   1895,  21,  p.  153. 


EFFICIENCY   IN   GRADE   WALKING.  249 

EFFICIENCY  IN  GRADE  WALKING. 
EFFICIENCY  IN  WORK  DUE  TO  GRADE-LIFT. 

^  efficiency  with  which  the  work  of  grade  walking  was  done  has 
been  computed  from  the  increment  in  the  heat-output  and  the  kilo- 
grammeters  of  work  performed  due  to  grade-lift,  the  value  of  426.6 
kg.  m.  being  used  as  the  mechanical  equivalent  of  1  calorie.1  In 
calculating  the  percentages,  2.34  gram-calories  is  taken  as  the  heat 
equivalent  of  1  kg.  m.  Since  the  heat  values  here  used  are  increments 
above  the  standing  and  horizontal- walking  requirements,  the  results 
represent  "net"  efficiencies.2 

A  study  of  these  efficiencies  in  relation  to  the  work  performed  in 
grade-lift  is  of  physiological  importance.  (See  column  q  of  tables  52 
to  55,  and  column  o  of  table  56.)  For  A.  J.  O.  and  W.  K.,  with  a  3.6 
per  cent  grade,  and  E.  D.  B.  with  a  5  per  cent  grade,  the  efficiencies 
are  all  high  (approximately  40  per  cent).  The  amounts  of  work  done 
on  these  low  grades  were  172  kg.  m.  for  A.  J.  0.,  and  under  150  kg.  m. 
for  W.  K.  and,  in  most  cases,  for  E.  D.  B.  This  amount  of  work  is 
equivalent  to  approximately  one-third  of  a  calorie  as  compared  with  the 
total  heat  measured  of  3  to  4  calories,  from  which  total  must  be  de- 
ducted the  standing  and  horizontal- walking  values.  An  error  of  0.1 
calorie  in  estimating  these  values  would  be  a  very  appreciable  amount 
of  the  one-third  calorie  attributable  to  the  work.  With  these  grades 
the  horizontal- walking  factor  was  determined  on  each  day  for  W.  K. 
and  E.  D.  B.  (except  for  one  day  in  April)  and  the  standing  value  was 
the  average,  with  E.  D.  B.,  of  23  determinations,  with  a  maximum  dif- 
ference of  0.13  calorie  and  a  maximum  deviation  from  the  average  of 
±0.07  calorie.  The  difference  between  the  average  standing  value  of 
1.10  calories  taken  for  W.  K.  and  the  two  standing  values  nearest  the 
date  on  which  he  walked  with  a  3.6  per  cent  grade  differ  by  only  0.01 
and  0.05  calorie.  These  variations  are  small,  and  while  they  might 
account  for  the  irregularities  in  the  efficiencies  for  the  different  days, 
they  would  not  account  for  the  constant  high  efficiencies  for  these  low 
grades.  We  are  inclined  to  the  opinion  that  the  subject  walking  on  a 
low  grade  and  performing  less  than  200  kg.  m.  of  work  did  so  at  an 
efficiency  in  the  neighborhood  of  40  per  cent.  With  250  kg.  m.  of 
work  and  upward,  the  efficiency  for  all  the  subjects  is  seen  to  approach 
30  per  cent. 

The  effect  of  the  speed  on  the  efficiency  with  which  the  work  was 
done  may  be  found  from  table  56,  in  which  the  figures  indicate  a  de- 
creasing efficiency  with  increasing  speed  for  a  definite  grade,  which 

1Armsby,  Principles  of  animal  nutrition,  New  York,  2d  ed.,  1906,  p.  233.  A  so-called  "best" 
value  of  426.7  is  reported  in  the  Smithsonian  Physical  Tables,  Washington,  1920,  table  212,  p.  197. 
Our  computations  were  made  previous  to  the  publication  of  this  edition  by  means  of  the  slightly 
lower  figure  of  426.6. 

2We  have  not  considered  "gross"  efficiency  in  this  discussion.  Obviously  all  the  data  for  its 
computation  are  readily  found  in  the  several  tables. 


250 


METABOLISM   DURING   WALKING. 


naturally  results  in  an  increased  amount  of  work.  To  compare  more 
directly  the  effect  on  the  efficiency  of  the  work  performed,  the  average 
efficiency  for  both  W.  K.  and  E.  D.  B.  with  increasing  amounts  of 
work  is  given  hi  table  69.  These  average  values  are  a  composite  for 
different  grades  and  speeds  and  show  in  each  case  that,  as  the  work 
increases,  the  efficiency  diminishes. 

TABLE  69. — Relation  between  efficiency  in  grade-lift  and  amount  of  work 
performed  in  grade  walking  by  W.  K.  and  E.  D.  5. 


Kg.  m.  of  grade 
lift. 

Efficiency. 

W.  K. 

E.D.B. 

400  to     500 
500  to     600 
600  to     700 
800  to  1,000 
1,000  to  1,600 

p.  ct, 
28.6 
26.2 
26.2 
25.8 

p.  ct. 
32.7 
32.5 
31.7 
30.0 
29.3 

When  the  periods  for  each  day  are  compared,  we  find  that  the  effi- 
ciency tends  to  fall  as  the  forenoon  progressed,  this  drop  being  apparent 
for  all  subjects,  grades,  and  speeds.  It  is  believed  that  this  is  due  to 
fatigue,  for  though  the  subject  may  not  be  conscious  of  it  for  some  hours, 
the  onset  of  fatigue  must  be  early  in  the  performance  of  work.  It  must 
be  admitted,  however,  that  no  connection  appears  between  the  amount 
of  the  decrease  hi  efficiency  and  the  amount  of  work  done.  Thus, 
with  E.  D.  B.  hi  the  two  periods  on  February  22,  when  he  did  over 
1,500  kg.  m.  of  work,  there  was  a  decrease  in  the  second  period  of  but 
0.5  per  cent,  while  on  several  days  when  he  performed  less  than  one- 
third  this  amount  of  work  the  efficiency  fell  during  the  forenoon 
1  to  2  per  cent.  It  is  perfectly  possible  that  the  subject's  physical 
condition  played  a  part  here  which  obscures  the  comparison. 

The  average  efficiencies  of  these  five  subjects  as  given  in  table  70  is 
33.4  per  cent;  if  we  exclude  A.  J.  O.,  with  whom  there  was  but  one 
experiment  with  a  low  grade,  we  find  the  average  to  be  31.3  per  cent. 
The  lowest  average  efficiency  was  with  W.  K.  at  29.4  per  cent,  and  the 
highest  with  E.  D.  B.  at  33.7  per  cent.  The  results  for  H.  R.  R.  are,- 
we  confess,  surprising.  From  our  observation,  which  was  influenced,* 
no  doubt,  by  the  fact  that  this  subject  practically  collapsed  after  the 
sixth  period  on  May  1,  while  performing  but  550  kg.  m.  of  work,  we 
expected  much  lower  efficiencies  from  him  than  from  the  others,  and 
yet  his  average  value  of  31.1  per  cent  is  in  accord  with  that  of  T.  H.  H. 
and  of  W.  K.  It  should  also  be  mentioned  that  in  the  last  period  of 
May  1,  just  before  he  succumbed,  the  efficiency  for  H.  R.  R.  was  not 
different  from  that  in  the  three  preceding  periods.  The  efficiencies  of 


EFFICIENCY   IN   GRADE   WALKING. 


251 


these  men  (omitting  A.  J.  O.)  lie  so  close  together  that  no  statement 
may  be  made  regarding  superiority.  The  fact  that  E.  D.  B.  stands 
somewhat  above  the  others  may  be  accounted  for  by  the  relatively 
large  number  of  experiments  in  which  there  was  a  small  amount  of 
work.  As  has  been  stated,  hi  all  such  experiments  the  subjects  show  a 
higher  efficiency  than  in  those  with  a  greater  amount  of  work.  There 
is  hardly  sufficient  ground  in  the  small  difference  for  E.  D.  B.  to  suppose 
that  as  an  individual  he  was  any  more  efficient  than  the  other  four  men. 

TABLE  70. — Efficiency  of  subjects  in  grade-walking  experiments. 


Subject. 

No.  of 
experi- 
ments. 

Efficiency  in  grade-lift. 

Minimum. 

Maximum. 

Average. 

A.  J.  O  

1 

6 
8 
48 
79 

p.  ci. 

p.  ct. 

p.  ct. 
41.8 
31.1 
30.8 
29.4 
33.7 

H.  R.  R  

29.3 
28.9 
25.2 
27.0 

32.5 
34.4 
44.2 
48.7 

T.  H.  H  

W.  K  

E.  D.  B  

Average  

33.4 
31.3 

Average  omitting  A.  J.  O  

Many  reports  on  the  mechanical  efficiency  of  men  doing  various 
forms  of  work  have  been  published.  One  of  the  earliest  was  that  of 
Edward  Smith,1  who  used  a  tread- wheel  and  from  whose  results 
Helmholtz2  computed  a  gross  efficiency  of  20  per  cent. 

A  large  amount  of  work  on  the  energy  exchange  in  man  during  walk- 
ing has  been  done  by  both  Zuntz  and  Durig  and  their  associates,  to 
which  reference  has  already  been  made.  (See  pp.  8  to  13.)  In  the 
summary  of  the  results3  given  in  table  71  and  obtained  with  men  walk- 
ing on  a  treadmill  at  grades  of  12.68  to  36.2  per  cent,  the  net  efficiencies 
range  from  25.7  to  46.5  per  cent,  with  a  distinct  tendency  to  approach 
33  per  cent.  This  is  hi  close  accord  with  our  results. 

The  efficiencies  of  men  performing  other  kinds  of  work,  such  as  using 
a  wheel  and  brake,  lifting  weights,  and  riding  a  stationary  bicycle, 
have  been  studied  by  a  number  of  investigators,  and  their  results  have 
been  discussed  by  Benedict  and  Cathcart.4  In  many  cases  there  is  no 
clear  distinction  between  the  "gross"  and  "net"  efficiency,  and  in 
several  studies  only  the  carbon-dioxide  output  is  determined.  Natur- 
ally, these  results  show  considerable  variation,  depending  upon  the 
subject,  the  form  of  work,  and  not  infrequently  upon  the  method  of 

iSmith,  Edward,  Phil.  Trans.,  1859,  149,  p.  681. 
2Helmholtz,  Proc.  Roy.  Inst.,  1861,  3,  p.  347. 

3Drawn  from  Durig,  Denkschr.  d.  math,  natur.  Klasse  d.  kaiserl.  Akad.  d.  Wissensch.,  1909, 
86,  p.  299. 

4Benedict  and  Cathcart,  Carnegie  Inst.  Wash.  Pub.  No.  187,  1913,  p.  101. 


252 


METABOLISM   DURING   WALKING. 


computation  employed.  It  may  be  said  that  these  net  efficiencies  are, 
as  a  rule,  lower  than  for  walking  and  are  nearer  27  to  28  per  cent  than 
they  are  to  33  per  cent.  The  first  studies  made  with  the  bicycle 
ergometer  were  carried  out  by  Atwater  and  Benedict1  and  showed  net 
efficiencies  of  19.6  per  cent  as  an  average  of  14  experiments.  Later 
experiments  reported  by  Benedict  and  Carpenter2  showed  efficiencies 
of  20  to  23  per  cent,  and  other  experiments  by  Benedict  and  Cathcart3 
with  a  professional  bicyclist,  M.  A.  M.,  gave  efficiencies  approaching 
33  per  cent. 

• 

TABLE  71. — Efficiency  of  men  in  treadmill  walking  with  different  grades,  as 
summarized  by  Durig.1     (Values  per  minute.) 


Grade  in 
per  cent. 

Grade-lift. 

Heat-output 
per  kg.  m.  of 
grade-lift. 

Efficiency. 

Experimenters. 

kg.  m. 

gm.-cal. 

p.  ct. 

31.0 

602.9 

8.68 

26.9 

459.6 

8.90 

•26.3 

594.4 

9.11 

25.7 

691.6 

8.89 

26.3 

31.0 

(620.0) 
774.3 

(6.98) 
8.58 

33.5 
27.3 

Schumburg  and  Zuntz. 

784.3 

8.14 

28.7 

810.5 

8.50 

25.7 

757.7 

8.21 

28.5 

763.1 

8.11 

22.9 
30.4 

555.0 
677.0 

6.82 
6.84 

34.3 
34.3 

A.  and  J.  Loewy  and  L. 

36.2 

812.0 

6.53 

35.8 

Zuntz. 

23.0 

6.430 

36.4 

s 

6.664 

35.1 

>  Frentzel  and  Reach. 

J 

12.68 

680.2 

5.488 

42.7 

12.68 

489.6 

5.402 

43.3 

12.68 
26.2 
12.68 

359.8 
795.1 
369.6 

6.064 
7.991 
7.223 

38.6 
29.3 
32.1 

Zuntz,    Loewy,    Muller, 
and  Caspari. 

12.68 

580.5 

7.057 

33.2 

18.24 

570.8 

5.033 

46.5 

21.6 
14.7 

830.3 
695.3 

6.73 
6.87 

34.9 
34.1 

JDurig.2 

1Durig,  Denkschr.  d.  math.-natur.  Klasse  d.  kaiserl.  Akad.  d.  Wissensch.,  1909,  86,  p.  299. 
*Ibid.,  p.  341.    An  apparent  typographical  error  in  the  average  for  the  heat-output  per  kilo- 
grammeter  of  grade-lift  for  21.6  per  cent  grade  has  been  corrected  here. 

It  may  be  stated,  therefore,  that  the  human  machine  can  accomplish 
various  forms  of  muscular  work  at  a  net  efficiency  greater  than  25  per 
cent,  and  that  grade  walking  is  the  most  efficient  of  the  various  forms 
of  exercise  thus  far  studied,  the  efficiency  for  this  probably  being  33  or 
more  per  cent. 


JAtwater  and  Benedict,  U.  S.  Dept.  Agr..  Office  Exp.  Sta.  Bull.  No.  136,  1903,  p.  190. 
*Benedict  and  Carpenter,  U.  S.  Dept.  Agr,,  Office  Exp.  Sta.  Bull.  208,  1909. 
'Benedict  and  Cathcart,  Carnegie  Inst.  Wash.  Pub.  No.  187,  1913,  p.  121. 


EFFICIENCY  IN   GRADE   WALKING.  253 

EFFICIENCY  IN  WORK  OF  ASCENT. 

The  total  heat-output  during  grade  walking  is  made  up  of  a  number 
of  factors:  first,  the  basal  requirement  for  standing;  second,  the  super- 
imposed work  of  forward  progression,  including  the  step-lift ;  and  third, 
the  actual  elevation  of  the  body  as  a  result  of  the  grade.  A  computa- 
tion of  the  proportion  of  energy  ascribable  to  the  actual  lifting  of  the 
body,  such  as  is  done  not  only  in  the  grade-lift  but  in  the  superimposed 
step-lift,  necessitates  the  deduction  of  certain  basal  values.  Of  these, 
obviously  that  for  the  standing  metabolism  would  be  one,  but  the 
deduction  of  the  standing  metabolism  only  does  not  allow  for  the 
energy  of  forward  progression.  Ordinarily,  the  entire  energy  due 
to  horizontal  walking  is  deducted  before  the  efficiency  for  grade  walk- 
ing is  computed,  but  this  is  illogical,  since  the  energy  required  for 
forward  progression  includes  a  not  inconsiderable  proportion  rightly 
attributable  to  the  elevation  of  the  body  in  the  step-lift,  which  is  an 
integral  factor  in  grade  walking.  When  the  increments  in  the  total 
heat  of  horizontal  walking  over  the  requirement  for  the  standing 
position  are  compared  with  the  computed  heat  ascribable  to  the  work 
done  by  the  body  in  the  step-lift,  it  is  seen  that  the  heat-output  due  to 
this  secondary  elevation  of  the  body  was  an  appreciable  percentage  of 
the  total  increase  in  energy  and  varied  with  the  speed  at  which  the 
man  walked.  (See  table  43,  p.  159.)  Consequently,  in  computing 
the  efficiency  for  the  work  of  ascent,  a  deduction  should  be  made  from 
the  total  heat-production  of  a  certain  proportion  of  the  energy  required 
for  horizontal  walking  at  a  similar  rate,  this  deduction  depending  upon 
the  speed  of  walking. 

It  has  seemed  unwise  to  use  all  of  our  data  in  computing  the  effi- 
ciency for  the  work  of  ascent,  inasmuch  as  the  method  of  computation 
is  at  best  based  upon  problematical  assumptions.  We  have,  however, 
computed  the  efficiency  for  a  number  of  typical  days  with  E.  D.  B.  at 
varying  grades  and  speeds.  These  results  are  recorded  in  table  72. 
This  table  is  best  considered  in  relation  to  table  55  (p.  209),  the  data  hi 
columns  a  to  e  being  drawn  from  that  table.  The  work  of  the  total 
lift  of  the  body,  that  is,  the  work  of  ascent,  which  includes  both  the 
grade-lift  and  the  step-lift  in  grade  walking,  is  recorded  in  column  c. 
The  total  increment  hi  the  heat  over  standing  in  column  d  represents 
the  total  heat  measured  during  the  grade  walking,  less  the  standing 
requirement.  The  total  heat  due  to  the  horizontal  component  is 
recorded  in  column  e  and,  as  originally  recorded  in  table  55,  was 
obtained  by  first  multiplying  the  weight  of  the  body  by  the  horizontal 
.component  of  the  distance  walked  and  then  multiplying  the  result  by 
the  factor  for  the  energy  required  for  each  horizontal  kilogrammeter 
(column  n  of  table  55). 

The  first  important  new  step  is  the  computation  of  the  heat  due  to  the 
horizontal  component,  less  that  fraction  due  to  the  step-lift  in  walking 


254 


METABOLISM   DURING   WALKING. 


on  a  level.  From  table  43,  the  percentage  of  the  increase  in  heat  due 
to  the  step-lift  in  horizontal  walking  may  be  computed  for  E.  D.  B. 
for  the  average  speeds.  These  percentages,  although  made  up  of 
somewhat  widely  varying  individual  values,  are  as  follows :  For  45  me- 
ters, 9  per  cent;  for  55  meters,  11  per  cent;  for  65  meters,  15  per  cent; 
for  72  meters,  16  per  cent;  and  for  77  meters,  18  per  cent.  The  pro- 
portions of  the  total  heat  for  the  horizontal  component  to  be  deducted 
from  the  total  heat  over  standing  are,  therefore,  for  a  speed  of  45  meters, 

TABLE  72. — Efficiency  for  work  of  ascent  of  E.  D.  B.1     (Average  values  per  minute.') 


(a) 

<&) 

(c) 

(d) 

Heat  due  to  horizontal 

Heat  due  to 

(JO 

Total 

component. 

work  of  ascent. 

Work  of 

incre- 

Efficiency 

Date. 

Grade. 

Dis- 
tance 
walked. 

total  lift 
(work  of 
ascent). 

ment 
in  heat 
over 
stand- 
ing. 

(e) 
Total. 

(/) 
Propor- 
tion due 
to  step- 

lift 

(0) 
Less  amount 
due  to 
step-lift. 

W 

Total. 
(d-g) 

(0 
Per  kg.m- 
of  work  of 
ascent. 

for  work 
of  ascent. 

2.34X100 

t 

11IL. 

eX(100-/) 

(h+c) 

100 

1915-16. 

p.  ct. 

meters. 

kg.  m. 

cals. 

cals. 

p.  ct. 

cals. 

cals. 

gm.-cals. 

p.  ct. 

Nov.    4 

5.0 

48.2 

198.1 

2.08 

1.25 

1.14 

0.94 

4.7 

49.8 

6 

5.0 

48.2 

200.7 

1.98 

1.23 

1.12 

.86 

4.3 

54.4 

17 

10.3 

48.0 

398.9 

3.20 

1.27 

1.16 

2.04 

5.1 

45.9 

Dec.     7 

15.0 

46.4 

555.5 

4.09 

1.20 

9    • 

1.09 

3.00 

5.4 

43.3 

Feb.     2 

25.0 

46.5 

976.4 

7.00 

1.27 

1.16 

5.84 

6.0 

39.0 

8 

30.0 

46.0 

1,104.8 

7.34 

1.22 

1.11 

6.23 

5.6 

41.8 

18 

40.0 

49.5 

1,526.6 

10.44 

1.26 

1.15 

9.29 

6.1 

38.4 

Nov.   9 

5.0 

54.8 

243.3 

2.24 

1.35 

1.20 

1.04 

4.3 

54.4 

10 

5.0 

55.4 

244.7 

2.19 

1.40 

1.25 

.94 

3.8 

61.6 

23 

10.0 

57.2 

484.1 

3.76 

1.39 

1.24 

2.52 

5.2 

45.0 

Dec.     8 

15.0 

58.3 

702.2 

5.28 

1.47 

1.31 

3.97 

5.7 

41.1 

17 

20.0 

53.4 

809.2 

5.55 

1.29 

11     • 

1.15 

4.40 

5.4 

43.3 

Feb.     3 

25.0 

52.6 

1,036.6 

7.63 

1.42 

1.26 

6.37 

6.1 

38.4 

9 

30.0 

53.6 

1,291.4 

8.80 

1.42 

1.26 

7.63 

5.9 

39.7 

16 

35.0 

57.6 

1,568.3 

11.10 

1.49 

1.33 

9.77 

6.2 

37.7 

21 

40.0 

57.1 

1,774.1 

12.50 

1.46 

1.30 

11.20 

6.3 

37.1 

Nov.  11 

5.0 

66.0 

299.6 

2.72 

1.76 

1.50 

1.22 

4.1 

55.8 

26 

10.0 

66.5 

586.8 

4.52 

1.69 

1.44 

3.08 

5.2 

45.0 

Dec.  13 

15.0 

66.8 

798.0 

5.84 

1.61 

1.37 

4.47 

5.6 

41.8 

20 

20.0 

66.4 

1,052.9 

7.14 

1.64 

•     15    - 

1.39 

5.75 

5.3 

44.2 

Jan.     5 

25.0 

69.3 

1,326.5 

9.90 

1.78 

1.51 

8.39 

6.3 

37.1 

Feb.  11 

30.0 

69.5 

1,676.6 

11.81 

1.84 

1.56 

10.25 

6.1 

38.4 

22 

40.0 

65.2 

1,996.5 

14.45 

1.66 

1.41 

13.04 

6.5 

36.0 

Nov.  13 

5.0 

74.1 

375.3 

3.16 

1.97 

1.65 

1.51 

4.0 

58.5 

Dec.     3 

10.0 

70.5 

650.8 

4.87 

1.85 

1.55 

3.32 

5.1 

45.9 

14 

15.0 

73.4 

909.5 

6.54 

1.92 

1.61 

4.93 

5.4 

43.3 

21 

20.0 

70.3 

1,078.8 

7.76 

1.72 

16     • 

1.44 

6.32 

5.9 

39.7 

Feb.     5 

25.0 

71.0 

1,429.1 

10.24 

1.91 

1.60 

8.64 

6.0 

39.0 

12 

30.0 

71.5 

1,710.6 

11.86 

1.91 

1.60 

10.26 

6.0 

39.0 

Nov.  30 

10.0 

78.5 

704.1 

5.62 

2.15 

}             { 

1.76 

3.86 

5.5 

42.5 

Dec.  16 

15.0 

81.3 

975.5 

7.29 

2.09 

1.71 

5.58 

5.7 

41.1 

31 

20.0 

80.1 

1,205.4 

9.94 

2.22 

!« 

18 

1.82 

8.12 

6.7 

34.9 

Feb.     7 

25.0 

75.9 

1,565.6 

11.42 

2.15 

1.76 

9.66 

6.2 

37.7 

table  55  (p.  209)  for  data  in  columns  a  to  e. 


EFFICIENCY   IN   GRADE   WALKING.  .      255 

100  per  cent  less  9  per  cent,  or  91  per  cent;  for  55  meters,  89  per  cent; 
for  65  meters,  85  per  cent;  for  72  meters,  84  per  cent;  and  for  77  meters, 
82  per  cent.  The  values  to  be  deducted  for  the  heat  due  to  the  hori- 
zontal component,  as  thus  computed,  are  given  in  column  g.  The  heat 
due  to  the  work  of  ascent  may  then  be  calculated  by  deducting  from  the 
total  increment  in  heat  over  standing  (column  d)  the  heat  due  to  the 
horizontal  component  corrected  for  that  due  to  the  step-lift  (column  g}. 
The  resulting  values  are  recorded  in  column  h,  and  represent  the  increase 
in  heat  actually  ascribable  to  the  work  of  ascent.  Dividing  these 
values  by  the  kilogrammeters  of  work  of  ascent  (column  c),  we  obtain 
the  increment  in  heat  per  kilogrammeter  of  work  of  ascent.  This  is 
best  expressed  in  gram-calories  as  recorded  in  column  i.  From  these 
latter  values  the  efficiency  of  the  body  for  the  total  work  of  ascent 
is  readily  computed  by  using  2.34  gram-calories  as  the  heat  equivalent 
of  1  kg.  m.  These  percentages  are  given  in  column  j,  and  represent 
net  efficiencies. 

From  the  general  consideration  of  the  efficiency  of  the  body  as  com- 
puted on  the  basis  of  grade-lift,  it  was  found  that  these  values  repre- 
sented an  average  for  all  of  the  subjects  not  far  from  33  per  cent.  (See 
table  70,  p.  251.)  By  this  new  method  of  computation,  which  ascribes 
a  larger  amount  of  work  to  the  body,  since  the  step-lift  is  superimposed 
upon  the  grade-lift,  we  find  that  for  this  subject  (E.  D.  B.)  the  per- 
centage of  efficiency  is  larger,  in  some  instances  actually  reaching  50  to 
60  per  cent,  with  a  maximum  on  November  10  of  61.6  per  cent.  Under 
the  separate  groupings  for  the  different  speeds,  the  experiments  have 
been  arranged  in  the  order  of  increasing  grade,  running  for  the  most 
part  from  5  to  40  per  cent,  except  with  the  two  higher-speed  groups 
when  the  steepest  grades  were  but  30  and  25  per  cent,  respectively. 
An  inspection  of  the  figures  for  these  efficiencies  in  column  j  shows  that, 
in  general,  the  percentages  fall  as  the  grade  increases,  i.  e.,  within  each 
speed  group  there  is  a  distinct  tendency  for  the  efficiency  to  be  some- 
what lower  with  the  higher  grades. 

It  is  more  than  likely  that  the  difficulty  in  computing  the  ratio  be- 
tween the  fraction  of  the  energy  expended  for  the  grade-lift  and  that 
expended  for  the  standing  and  horizontal  walking  when  an  extremely 
low  grade  was  employed  may  in  part  account  for  the  high  values 
here  found,  a  point  which  has  been  touched  upon  in  the  earlier  dis- 
cussion of  the  grade-lift  measurements.  With  constant  grade,  but 
varying  speeds,  the  percentage  efficiency  for  the  10  per  cent  grade 
remains  practically  constant  throughout  the  entire  series  at  45  per 
cent;  with  the  15  per  cent  grade  they  likewise  are  reasonably  constant; 
with  a  30  per  cent  grade  a  slight  decrease  in  the  efficiency  is  apparent, 
which  may  also  be  seen  with  the  40  per  cent  grade. 

The  whole  problem  of  computing  the  efficiency  on  this  basis  may 
reasonably  be  challenged  on  the  grounds  that  not  only  is  the  value  of 
the  step-lift  uncertain,  but  also  we  are  not  dealing  here  with  "effective" 


256  METABOLISM   DURING   WALKING. 

external  muscular  work.  The  transportation  of  the  body  up-grade 
or  the  transportation  of  a  superimposed  load,  such  as  was  done  in  many 
of  Durig's  experiments,  may  definitely  be  classed  as  "effective"  mus- 
cular work.  The  step-lift,  both  with  the  body  and  with  the  superim- 
posed load,  can  not  be  considered  in  the  ordinary  process  of  walking 
as  effective  external  work.  Nevertheless  we  believe  that  this  treat- 
ment has  distinct  physiological  interest  in  the  strong  suggestion  that 
attention  to  the  type  of  gait,  particularly  in  minimizing  the  step-lift, 
may  not  be  without  definite  economic  importance  in  considering  the 
human  body  as  an  efficient  machine. 

EFFECT  OF  LAMENESS  UPON  THE  EFFICIENCY  OF  E.  D.  B. 

As  has  been  stated  elsewhere,  E.  D.  B.  developed  a  lameness  in  the 
instep  of  his  right  foot  early  in  January.  As  a  result,  the  experiments 
with  him  were  discontinued  for  a  period  of  three  weeks,  beginning  with 
January  10.  On  inquiry  it  developed  that  he  had  been  conscious  of 
some  pain  in  the  instep  for  a  number  of  days,  although  he  had  made  no 
complaint.  The  question  accordingly  arose  whether  the  lameness  was 
of  sufficient  moment  to  vitiate  the  results  of  the  standing  and  grade- 
walking  experiments  on  January  3,  4,  and  5.  The  metabolism  data 
obtained  on  these  days  have  accordingly  been  collected  in  table  73. 
For  comparison,  the  data  are  included  for  the  standing  experiment  of 
December  31  and  the  grade- walking  experiment  of  January  1  before 
the  lameness  developed,  and  for  the  grade-walking  experiment  of 
February  4,  when  the  lameness  had  been  cured  by  three  weeks  of  rest. 

As  would  be  expected,  the  metabolism  during  standing  was  evi- 
dently not  affected,  as  the  data  for  January  3,  4,  and  5  agree  well  with 
those  obtained  on  December  31,  before  the  lameness  developed.  In 
the  grade-walking  experiments  of  January  3  and  4,  the  values  for  the 
energy  cost  per  kilogrammeter  and  the  percentage  efficiencies  show 
slight  changes  from  corresponding  data  obtained  on  January  1  and 
February  4;  nevertheless  the  differences  are  so  slight  that  they  may  be 
considered  as  within  the  limits  of  experimental  error.  The  efficiency 
for  the  other  day  (January  5)  agrees  well  with  those  of  January  1  and 
February  4.  There  is  therefore  no  reason  to  discredit  the  values  re- 
ported for  these  three  days. 

On  January  10,  when  the  subject  began  walking  preliminary  to  the 
experimental  period,  the  pain  in  his  instep  was  so  severe  that  it  was 
necessary  to  end  the  experiment.  The  standing  data  for  this  day  have 
not  been  included  hi  any  of  the  tables  previously  discussed,  but  are 
given  in  table  73.  These  values  show  a  very  slight  increase  in  the 
carbon-dioxide  production  and  heat-output.  Although  it  was  noted  in 
the  protocols  of  the  experiment  that  the  subject  "stood  mostly  on  the 
left  foot"  and  "favored  his  right  leg,"  the  difference  in  the  metabolism 
values  is  too  small  to  indicate  that  the  subject  was  standing  at  a  dis- 


PHYSIOLOGICAL   EFFECTS   OF   GRADE   WALKING. 


257 


advantage.  Zuntz  and  Schumburg1  report  that  when  one  of  their 
subjects  walked  with  a  lame  foot,  the  metabolism  increased  9.2  per 
cent.  This  might  well  have  occurred  with  E.  D.  B.  on  January  10  had 
we  insisted  on  continuing  the  experiment,  as  his  lameness  caused  him 
great  discomfort  in  walking.  On  January  3,  4,  and  5,  the  lameness 
was  apparently  of  too  little  account  to  affect  his  efficiency. 

TABLE  73. — Effect  of  slight  lameness  upon  the  metabolism  and  efficiency  of  E.  D.  B.     (Value* 

per  minute.) 


Date  and  conditions. 

Carbon 
dioxide. 

Oxygen. 

Respiratory 
quotient. 

Heat-output. 

Standing: 

No  lameness: 

c.  c. 

c.  c. 

cals. 

Dec.  31  

211 

257 

0  82 

1  24 

Slightly  lame: 

Jan.     3  

210 

250 

.84 

1  21 

4  

212 

244 

.87 

1.19 

5  

206 

253 

.81 

1  22 

Too  lame  to  walk  grade: 

Jan.   10  

224 

251 

.89 

1.23 

Heat- 

Date  and  conditions. 

Work  due 
to  grade- 
lift. 

Carbon 
dioxide. 

Oxygen. 

Respira- 
tory 
quotient. 

output 
per  kg.  m. 
of  grade- 

Efficiency. 

lift. 

Grade  walking: 

No  lameness: 

kg.  m. 

c.  c. 

c.  c. 

gm.-cals. 

p.  ct. 

Jan.      1  

935 

2,010 

2,272 

0.88 

8.3 

28.2 

Feb.     4  

932 

1,903 

2,084 

.91 

8.0 

29.2 

Slightly  lame: 

Jan.     3  

628 

1,183 

1,451 

.82 

7.5 

31.2 

4  

872 

1,723 

1,965 

.88 

7.8 

30.0 

5  

993 

2,054 

2,252 

.91 

8.2 

28.5 

PHYSIOLOGICAL  EFFECTS  OF  GRADE  WALKING. 
RESPIRATION-RATE  DURING  GRADE  WALKING. 

The  respiration-rates  during  the  experiments  with  grade  walking 
(see  tables  13  to  16,  pp.  69  to  78)  tended  to  increase  slightly  in  each 
period  as  the  forenoon  progressed.  This  increase,  hi  a  few  instances, 
was  as  large  as  5  respirations  per  minute,  but  in  the  majority  of  cases 
it  was  only  1  or  2  respirations  per  minute  over  that  of  the  first  walking 
period.  The  increase  between  periods  does  not  appear  to  be  associated 
with  the  amount  of  work  which  the  subject  was  performing,  and  the 
differences  were  no  greater  when  the  larger  amounts  of  work  were  done. 

The  average  respiration-rates  are  also  given  in  table  56  (p.  221),  in 
which  the  experimental  data  have  been  grouped  according  to  the  grade 


JZuntz  and  Schumburg,  Physiologic  des  Marsches,  Berlin,  1901,  p.  265. 


258 


METABOLISM   DURING   WALKING. 


and  speed  of  walking,  and  not  according  to  the  sequence  of  the  experi- 
ments. As  a  rule,  the  changes  in  the  rates  progressed  gradually  and 
uniformly  with  the  increase  in  the  speed  and  the  amount  of  work  per- 
formed. The  maximum  rate  was  found  with  the  maximum  work  with 
each  subject,  although  this  is  not  true  of  the  minimum  amount  of  work. 
The  difference  in  the  respiration-rates  for  the  different  subjects  is 
noticeable.  At  the  medium  speed  of  60  to  65  meters  per  minute  with  a 
10  per  cent  grade,  T.  H.  H.  had  a  low  rate  of  17.9  as  compared  with 
W.  K.'s  rate  of  26.1;  E.  D.  B.  had  a  rate  of  26.7  when  walking  on  a  25 
per  cent  grade  at  70  to  75  meters  per  minute  as  compared  with  W.  K.'s 
rate  of  40  under  similar  conditions. 


170 
160 
150 

140 
R 

130    40 
120    35 
110    30 
25 

/ 

V 
Liter 

55 
45 
35 
25 
15 

" 

/ 

X« 

jy 

X 

^ 

/, 

X 

/j 

,. 

/ 

X 

X  " 

x. 

* 

« 

9 

-^ 

^ 

X 

2O 

*  

. 

X 

7 

^ 

x.PL 

USE 
5PIRATI 
ITILAf 

DN  

ON 

—•  —-1 

r<^ 

*V 

a.  RE 
+-VE 

IOO             300             500             700            900 
Kg.ms. 

FIG.  28. — Pulse-rate,  respiration-rate,  and 
pulmonary  ventilation  of  W.  K.  during 
grade  walking,  referred  to  kilogram- 
meters  of  work.  (Values  per  minute  from 
table  56.) 

The  curves  for  the  average  respiration-rates  for  W.  K.  and  E.  D.  B. 
in  table  56  have  been  plotted  and  presented  in  figures  28  and  29.  The 
curve  for  E.  D.  B.  shows  a  uniform  rate  of  increase,  but  that  for  W.  K. 
indicates  a  greater  rate  of  increase  beyond  300  kg.  m.  From  these 
curves  an  estimate  has  been  made  of  the  respiration-rates  per  minute 
for  increasing  amounts  of  work.  (See  second  column  of  tables  74  and 
75.)  From  these  values  have  been  calculated  the  total  and  percent- 
age increases  hi  the  respiration-rate  over  the  standing  requirement, 
and  also  the  increments  per  100  kg.  m.  as  the  unit  of  work  done.  The 


PHYSIOLOGICAL   EFFECTS   OF   GRADE   WALKING. 


259 


rapid  increase  in  the  respiration-rate  of  W.  K.  as  the  work  increased 
manifests  itself  here  in  an  increase  over  the  standing  requirement  per 
100  kg.  m.  of  work,  while  for  E.  D.  B.  the  increase  per  100  kg.  m. 
diminished  as  the  amount  of  work  became  larger  and  reached  con- 
stancy at  about  800  to  900  kg.  m.  The  percentage  increase  over  the 
standing  value  for  W.  K.  ranged  from  16  to  nearly  100  per  cent,  with 
an  increase  per  100  kg.  m.  of  7  to  11  per  cent.  With  E.  D.  B.  the 
increase  was  as  high  as  40  per  cent  for  the  first  100  kg.  m.,  but  it  fell 
rapidly  and  above  700  kg.  m.  the  increase  per  100  kg.  m.  was  con- 
stant at  a  level  of  7  and  8  per  cent. 


160O 


FIG.  29. — Pulse-rate,  respiration-rate,  and  pulmonary  ventilation  of  E. 
D.  B.  during  grade  walking,  referred  to  kilogrammeters  of  work. 
(Values  per  minute  from  table  56.) 

TABLE  74. — Respiration-rale  of  W.  K.  with  increasing  amounts  of  work  in 
grade-walking  experiments  without  food.     (Values  per  minute.)1 


Increase  over  stand- 

Percentage increase 

Respiration- 

ing  rate  (21.1) 

over  standing  rate. 

Kg.  m. 

rate  during 

of  work. 

grade 

walking. 

Total. 

Per  100 
kg.  m. 

Total. 

Per  100 
kg.  m. 

200 

24.5 

3.4 

1.7 

16 

8 

300 

25.3 

4.2 

1.4 

20 

7 

400 

26.8 

5.7 

1.4 

27 

7 

500 

28.6 

7.5 

1.5 

36 

7 

600 

31.3 

10.2 

1.7 

48 

8 

700 

34.3 

13.2 

1.9 

63 

9 

800 

38.0 

16.9 

2.1 

80 

10 

900 

41.7 

20.6 

2.2 

98 

11 

^aaed  upon  figure  28. 


260 


METABOLISM   DURING  WALKING. 


TABLE  75. — Respiration-rate  of  E.  D.  B.  with  increasing  amounts  of  work  in 
grade-walking  experiments  without  food.     (Values  per  minute.}1 


Kg.  m. 
of  work. 

Respiration- 
rate  during 
grade 
walking. 

Increase  over  stand- 
ing rate  (15.4) 

Percentage  increase 
over  standing  rate. 

Total. 

Per  100 
kg.  m. 

Total. 

Per  100 
kg.  m. 

100 

21.5 

6.1 

6.1 

40 

40 

200 

22.0 

6.6 

3.3 

43 

22 

300 

23.0 

7.6 

2.5 

49 

17 

400 

23.6 

8.2 

2.1 

53 

13 

500 

24.1 

8.7 

1.7 

56 

11 

600 

24.5 

9.1 

1.5 

59 

10 

700 

25.0 

9.6 

1.4 

62 

9 

800 

25.7 

10.3 

1.3 

67 

8 

900 

26.5 

11.1 

1.2 

72 

8 

1,000 

27.5 

12.1 

1.2 

79 

8 

1,100 

28.0 

12.6 

1.1 

82 

7 

1,200 

29.1 

13.7 

1.1 

89 

7 

1,300 

30.5 

15.1 

1.2 

98 

8 

1,400 

31.6 

16.2 

1.2 

105 

8 

1,500 

32.8 

17.4 

1.2 

113 

8 

JBased  upon  figure  29. 
PULMONARY  VENTILATION  DURING  GRADE  WALKING. 

The  data  for  the  puhnonary  ventilation  during  the  grade-walking 
experiments  are  also  given  in  detail  in  tables  13  to  16,  pages  69  to  78, 
from  which  it  is  seen  that  though  on  some  days  the  ventilation  increased 
from  period  to  period,  this  increase  was  not  so  pronounced  and  appears 
to  be  much  more  nearly  uniform  and  less  influenced  by  continued  exer- 
cise than  was  the  case  with  the  respiration-rate.  Naturally  the  volume 
varied  with  the  individual  subjects  and  primarily  with  the  amount  of 
work  that  was  performed.  The  variations  in  the  rate  of  increase  due 
to  increases  in  grade  and  speed  are  best  seen  in  the  group  averages  hi 
table  56,  from  which  it  is  evident  that,  almost  without  exception,  the 
average  ventilation  increased  with  each  increase  in  speed  for  the  several 
grades  or  each  increase  in  grade  for  a  uniform  speed.  The  figures  thus 
give  some  indication  of  what  may  be  required  by  a  person  when  doing  a 
definite  amount  of  muscular  work.  The  significance  of  these  figures 
in  the  designing  of  suitable  gas-masks  is  obvious.  In  general,  it  may 
be  said  that  17  to  21  liters  per  minute  represents  the  average  rate  for  a 
moderate  speed  of  50  to  60  meters  per  minute  (approximately  2  miles 
an  hour)  when  the  subject  is  walking  on  a  10  per  cent  grade,  or  when 
he  is  doing  approximately  335  kg.  m.  of  work.  The  amount  of  ventila- 
tion increased  as  the  grade  and  speed  increased  to  a  maximum  of  85 
liters  per  minute,  as  in  the  case  of  E.  D.  B.  with  1,569  kg.  m.  of  work. 

As  previously  stated  (see  p.  192),  the  use  of  the  mouthpiece  in  these 
grade- walking  experiments  did  not  apparently  affect  the  normality  of 
the  results  obtained  for  the  respiration-rate  and  the  pulmonary  venti- 
lation, notwithstanding  the  quickened  respiration  and  greater  ventila- 
tion as  a  consequence  of  the  severe  exercise. 


PHYSIOLOGICAL   EFFECTS   OF   GRADE   WALKING. 


261 


The  ventilation-rates  for  W.  K.  and  E.  D.  B.  have  been  plotted  and  are 
included  with  the  respiration  curves  hi  figures  28  and  29,  based  on  kilo- 
grammeters  of  work  performed.  In  these  two  curves  the  total  venti- 
lations of  W.  K.  and  E.  D.  B.  are  practically  the  same  for  like  amounts 
of  work  up  to  500  kg.  m. ;  beyond  this  point  the  total  ventilation  of  W. 
K.  exceeds  that  of  E.  D.  B.  for  similar  amounts  of  work.  From  the 
curves  hi  figures  28  and  29,  an  estimate  has  been  made  of  the  venti- 
lation requirements  for  increasing  amounts  of  work.  (See  tables  76 
and  77.)  From  these  values  are  found  the  total  and  percentage  in- 

TABLE  76. — Pulmonary  ventilation  of  W.  K.  with  increasing  amounts  of  work  in 
grade-walking  experiments  without  food.     (Values  per  minute.)1 


Increase  over  stand- 

Percentage increase 

Kg.  m. 
of  work. 

Pulmonary 
ventilation 
(reduced). 

ing  rate  (6.5  liters). 

over  standing  rate. 

Total. 

Per  100 
kg.  m. 

Total. 

Per  100 
kg.  m. 

liters. 

liters. 

liters. 

200 

16 

9.5 

4.8 

146 

73 

300 

19 

12.5 

4.2 

192 

64 

400 

22 

15.5 

3.9 

238 

60 

500 

26 

19.5 

3.9 

300 

60 

600 

31 

24.5 

4.1 

377 

63 

700 

39 

32.5 

4.6 

500 

71 

800 

47 

40.5 

5.1 

623 

78 

900 

57 

50.5 

5.6 

777 

86 

'Based  upon  figure  28. 

TABLE  77. — Pulmonary  ventilation  of  E.  D.  B.  with  increasing  amounts  of  work 
in  grade-walking  experiments  without  food.    ( Values  per  minute.) l 


Increase  over  stand- 

Percentage increase 

Kg.  m. 
of  work. 

Pulmonary 
ventilation 
(reduced). 

ing  rate  (9.1  liters). 

over  standing  rate. 

Total. 

Per  100 
kg.  m. 

Total. 

Per  100 

kg.  m. 

liters. 

liters. 

liters. 

200 

16 

6.9 

3.5 

76 

38 

300 

19 

9.9 

3.3 

109 

36 

400 

22 

12.9 

3.2 

142 

36 

500 

26 

16.9 

3.4 

186 

37 

600 

29 

19.9 

3.3 

219 

37 

700 

32 

22.9 

3.3 

252 

36 

800 

37 

27.9 

3.5 

307 

38 

900 

41 

31.9 

3.5 

351 

39 

1,000 

46 

36.9 

3.7 

405 

41 

1,100 

51 

41.9 

3.8 

460 

42 

1,200 

57 

47.9 

4.0 

526 

44 

1,300 

64 

54.9 

4.2 

603 

46 

1,400 

71 

61.9 

4.4 

680 

49 

1,500 

79 

69.9 

4.7 

768 

51 

1,600 

87 

77.9 

4.9 

857 

54 

on  figure  29. 


262  METABOLISM   DURING   WALKING. 

creases  over  the  standing  requirements  as  well  as  the  increase  over  the 
standing  requirements  per  100  kg.  m.  of  work  performed.  These  figures 
show  an  increment  over  the  standing  requirement  of  777  per  cent  for 
W.  K.  for  900  kg.  m.  and  857  per  cent  for  E.  D.  B.  for  1,600  kg.  m.  of 
work.  For  a  unit  amount  of  work  of  100  kg.  m.,  however,  there  is  a 
gradual  decrease  up  to  600  kg.  m.  for  W.  K.  and  to  800  kg.  m.  for  E. 
D.  B.  Beyond  these  points  the  ventilation  per  100  kg.  m.  increased 
hi  each  case,  reaching  5.6  liters  for  W.  K.  as  compared  with  3.5  liters 
for  E.  D.  B.  at  900  kg.  m. 

PULSE-RATE  DUHINQ  GRADE  WALKING. 

The  pulse-rates  for  a  definite  grade  and  speed  of  walking  are  influenced 
hi  these  experiments  by  several  factors,  but  chiefly  by  (1)  the  daily  rate 
for  the  standing  position,  which,  as  seen  from  tables  3  to  7,  shows 
variation  from  day  to  day;  and  (2)  the  variation  in  the  speed  at  which 
the  subject  walked,  due  to  our  inability  to  control  exactly  the  speed  of 
the  treadmill.  Furthermore,  it  is  noticeable  hi  the  data  in  tables  13  to 
16  that  almost  without  exception  the  average  pulse-rate  increased  with 
each  succeeding  period.  As  has  been  stated,  the  pulse-rates  for  the 
individual  periods  represent  an  average,  in  most  cases,  of  3  one-minute 
records.  This  increase  from  period  to  period  may,  in  some  cases,  be 
due  to  the  gradual  alteration  in  the  speed  at  which  the  subject  walked; 
but  since  there  are  numerous  instances  when  the  pulse-rate  increased 
though  the  speed  decreased,  the  increment  hi  pulse-rate  is  more  likely 
due  to  fatigue  with  the  continuation  of  the  work.  The  increase  from 
period  to  period  is  seen  to  have  a  variation  of  from  2  to  3  beats  per 
minute  to  as  high  as  15  beats,  with  a  total  accumulated  increase  in  the 
pulse-rate  during  a  forenoon  in  a  few  instances.of  as  much  as  30  beats 
a  minute  while  the  same  work  is  being  performed.  This  rise  in  the 
pulse-rate,  due  to  the  cumulative  effect  of  the  exercise,  makes  the  values 
given  as  the  average  for  the  day  misleading,  for  an  average  made  up  of  5 
or  6  continuous  walking  periods  would  be  much  higher  than  when  but 
half  that  number  of  walking  periods  are  included  in  the  experiment. 
Furthermore,  any  failure  to  secure  the  record  of  the  pulse-rate  for  a 
period  tends  to  change  the  average  value  reported  for  the  day. 

In  spite  of  these  difficulties  and  of  the  recognized  objection  to  these 
so-called  daily  averages,  it  is  believed  that  the  errors  that  are  present 
are  minimized  to  a  considerable  extent  by  the  number  of  the  experi- 
ments and  that  the  general  picture  is  correct.  An  inspection  of  the 
daily  averages  in  tables  13  to  16  shows  an  approximate  pulse-rate  for 
an  approximate  amount  of  work  performed.  This  is  more  apparent  in 
table  56,  in  which  the  values  are  not  averages  for  the  individual  days, 
but  for  the  periods  falling  within  5-meter  speed  groups  with  different 
grades. 


PHYSIOLOGICAL   EFFECTS   OF   GRADE   WALKING.  263 

The  high  pulse-rate  of  H.  R.  R.  in  most  of  the  standing  and  hori- 
zontal-walking experiments  persists,  also,  in  the  grade  experiments,  in 
which  a  rate  of  140  was  found  with  the  subject  walking  on  a  10  per  cent 
grade  at  a  speed  of  60  to  65  meters  per  minute  (about  2.5  miles  an  hour), 
as  compared  with  a  rate  of  125  and  103  for  W.  K.  and  E.  D.  B.,  re- 
spectively, under  similar  conditions.  (See  table  56.) 

T.  H.  H.  shows  the  exceptional  behavior  of  a  falling  pulse  with  in- 
crease in  the  speed  for  the  single  grade  used  in  his  experiments.  This 
is  due,  hi  part,  to  the  considerable  number  of  periods  on  April  6  and  7, 
when  all  of  the  period  data  for  the  lowest  speed  (55  to  60  meters  per 
minute)  were  obtained.  Out  of  the  9  periods  composing  the  average 
for  a  speed  of  55  to  60  meters  a  minute,  the  3  highest  were  the  last 
records  of  a  continuous  forenoon  performance  on  April  7  of  6  periods. 
The  average  pulse-rate  for  this  speed  was  therefore  high  on  account  of 
the  cumulative  effect  of  the  work  on  these  days.  However,  this  will 
not  entirely  account  for  the  fact  that  this  subject  had  a  decreasing  pulse- 
rate  with  increasing  work.  On  April  15,  when  he  performed  his  largest 
amount  of  work,  his  pulse-rate  was  distinctly  lower  than  on  the  pre- 
vious days.  A  week  intervened  between  this  experiment  and  the  pre- 
ceding one,  but  we  have  no  record  that  his  physical  condition  was 
different  in  this  experiment  from  that  in  any  other.  Evidently  the 
experiments  with  T.  H.  H.  were  not  continued  long  enough  to  deter- 
mine his  representative  pulse-rate  in  the  performance  of  a  moderate 
amount  of  exercise. 

W.  K.  and  E.  D.  B.  offer  more  data  for  comparison.  These  values 
indicate  that,  with  occasional  exceptions,  the  pulse-rate  progressed 
with  the  speed  for  each  grade.  The  increase  in  the  pulse-rate  in  rela- 
tion to  the  amount  of  work  performed  is  depicted  in  the  curves  for 
these  subjects  in  figures  28  and  29,1  which  are  based  upon  the  averages 
in  table  56.  They  indicate  a  practically  uniform  increase  with  increase 
in  the  amount  of  work  done.  The  curve  for  W.  K.  ascendfs  more 
sharply  than  that  for  E.  D.  B.,  the  average  pulse-rate  increasing  from 
115  to  176  beats  for  an  increase  from  298  to  891  kg.  m.,  or  approximately 
one  beat  for  every  9.7  kg.  m.  increase  in  work,  while  the  average  pulse- 
rate  of  E.  D.  B.  increased  from  84  to  186  beats  for  an  increase  in  work 
from  59  to  1,569  kg.  m.,  or  an  increase  of  one  beat  for  every  14.8  kg.  m. 
increase  in  work.  If  these  values  are  referred  to  the  average  basal  value 
found  in  the  standing  experiments  (79  for  W.  K.  and  78  for  E.  D.  B.), 
the  increase  for  the  maximum  amount  of  work  is  found  to  ba  123  per 
cent  for  891  kg.  m.  with  W.  K.  and  138  per  cent  for  1,569  kg.  m.  with 
E.  D.  B.  This  would  correspond  to  an  increase  of  approximately 
7  kg.  m.  for  every  1  per  cent  of  increase  in  the  pulse-rate  for  W.  K.  and 
llkg.  m.  for  E.  D.  B. 

'All  of  the  curves  in  these  two  figures  represent  averages  of  estimates  drawn  independently 
by  three  members  of  the  Laboratory  staff. 


METABOLISM   DURING   WALKING. 


Comparing  these  increases  in  the  pulse-rate  with  the  increases  in  the 
oxygen  consumption  for  like  amounts  of  work,  we  find  that  with  W.  K., 
when  he  was  doing  the  maximum  amount  of  891  kg.  m.  of  work,  the 
increase  in  the  oxygen  consumption  over  his  standing  requirement  was 
818  per  cent,  and  with  E.  D.  B.  for  1,569  kg.  m.,  the  increase  was  1,205 
per  cent.  (See  table  57,  p.  224.)  This  shows  the  enormous  increase  in 
the  oxygen  consumption  as  compared  with  the  increase  in  the  pulse- 
rate.  How  this  great  increase  in  oxygen  consumption  is  provided 
for  is  still  undetermined.  Certainly,  neither  the  increase  in  the  pulse- 
rate  nor  any  probable  increase  in  the  oxygen-carrying  capacity  of  the 
blood  due  to  the  more  complete  combination  with  the  hemoglobin  can 
account  for  it,  and  an  increase  in  the  volume  output  of  the  heart, 
with  perhaps  a  large  pulmonary  oxidation1  under  these  conditions, 
seems  probable. 

TABLE  78. — Pulse-rate  of  W.  K.  with  increasing  amounts  of  work  in  grade- 
walking  experiments  without  food.     (Values  per  minute.)1 


Increase 

Percentage  increase 
over  standing  rate. 

Kg.  m. 
of  work. 

Pulse- 
rate. 

over 
standing 

rate 
(79). 

Total. 

Per  100 
kg.  m. 

p.  ct. 

p.  ct. 

300 

112 

33 

42 

14 

400 

122 

43 

54 

14 

500 

133 

54 

68 

14 

600 

144 

65 

82 

14 

700 

155 

76 

96 

14 

800 

166 

87 

110 

14 

900 

177 

98 

124 

14 

upon  figure  28,  p.  258. 

From  the  curves  in  figures  28  and  29,  estimates  may  be  made  of  the 
increase  in  pulse-rate  with  increasing  amounts  of  twork,  as  was  done 
for  the  total  oxygen  consumption,  total  heat-output,  and  other  factors. 
These  estimates  are  recorded  in  tables  78  and  79,  together  with  the 
increase  over  the  average  values  for  the  standing  experiments.  The 
percentage  increases  in  the  last  column  of  these  tables  show  that  with 
W.  K.  the  pulse-rate  increased  14  per  cent  for  each  100  kg.  m.  of  work 
done  over  his  average  pulse-rate  of  79  during  standing;  with  E.  D.  B. 
the  increase  over  his  standing  average  of  78  was  more  nearly  10  per 
cent  for  each  100  kg.  m.  The  increase  in  the  oxygen  consumption  on 
this  same  basis  varied  from  139  to  97  per  cent  for  W.  K.  and  from  150 
to  77  per  cent  for  E.  D.  B.  (See  tables  58  and  59,  p.  229.)  The 
approximation  to  constancy  in  the  percentage  increase  of  the  pulse- 
rate  with  each  100  kg.  m.  of  work  is  in  marked  contrast  to  the  fall  in 

Henderson,  Am.  Journ.  Physiol.,  1912-13,  31,  p.  352. 


PHYSIOLOGICAL  EFFECTS   OF   GRADE   WALKING. 


265 


TABLE  79. — Pulse-rate  of  E.  D.  B.  with  increasing  amounts  of  work  in  grade- 
walking  experiments  without  food.     (Values  per  minute.}1 


Increase 

Percentage  increase 
over  standing  rate. 

Kg.  m. 
of  work. 

Pulse- 
rate. 

over 
standing 

rate 
(78). 

Total. 

Per  100 
kg.  m. 

j>.  ct. 

p.  ct. 

100 

85 

7 

9 

9 

200 

95 

17 

22 

11 

300 

103 

25 

32 

11 

400 

111 

33 

42 

11 

500 

119 

41 

53 

11 

600 

126 

48 

62 

10 

700 

133 

55 

70 

10 

800 

140 

62 

80 

10 

900 

147 

69 

88 

10 

1,000 

153 

75 

96 

10 

1,100 

159 

81 

104 

9 

1,200 

165 

87 

112 

9 

1,300 

171 

93 

119 

9 

1,400 

177 

99 

127 

9 

1,500 

184 

106 

136 

9 

1,600 

189 

111 

142 

9 

'Based  upon  figure  29. 

the  percentage  increase  over  the  standing  requirement  for  the  oxygen 
consumption  with  each  100  kg.  m.  of  work,  clearly  indicated  in  tables 
58  and  59. 

In  figures  30  to  32,  a  few  typical  curves  are  given  of  the  pulse-rates 
of  E.  D.  B.  during  grade  walking  with  the  accompanying  changes  before 
and  after  the  exercise.  The  pulse-rates  immediately  preceding  and 
following  the  beginning  and  end  of  the  exercise  will  be  considered  in 
another  section  in  discussing  the  transitional  periods  for  changes  in 


FIG.  30. — Typical  pulse  curves  of  E.  D.  B.,  with  subject 
standing,  walking  on  a  level,  and  walking  on  an  incline. 
(Values  per  minute.) 

2,  subject  standing;  3*,  walking  on  a  level;  3**,  walking  on 
an  incline.  Black  points,  records  during  experimental 
periods;  open  circles,  records  between  periods.  Curve 
A,  Nov.  5;  B,  Nov.  6,  1915. 


266 


METABOLISM   DURING   WALKING. 


180 
160 
140 
120 
100 
80 

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conditions  (pp.  297  to  305).  As  in  similar  figures,  the  number  1  in- 
dicates that  the  subject  was  sitting,  and  2  that  he  was  standing.  The 
time  at  which  the  subject  began  walking  is  indicated  by  the  figure  3.1 
The  points  indicated  by  open  circles  represent  per  minute  values  ob- 
tained in  the  interval  between  the  experimental  periods. 

Curve  A  in  figure  30  gives  a  picture  of  the  rate  when  the  subject  was 
walking  on  a  level  up  to  10h  33m  a.  m.,  stood  until  10h  40™  a.  m.,  and 

thereafter  walked  on  a  5  per 
cent  grade  until  12h  27m  p.  m., 
when  he  again  stood  for  a  short 
tune.  The  course  of  the  curve 
is  but  little  altered  by  the 
change  to  grade  walking,  and 
there  were  no  sudden  or  marked 
variations  in  the  rate  during  the 
forenoon.  Curve  B  in  figure  30 
is  also  for  an  experiment  with  a 
_  5  per  cent  grade  preceded  by 
12°°  walking  on  a  level,  but  on  this 
day  the  speed  was  a  little 
higher.  Curve  B  has  the  same 
general  appearance  as  curve  A, 
however,  except  that  the  rise 
due  to  the  walking  is  somewhat 
more  marked.  Both  curves  in- 
dicate a  slight  fall  at  the  begin- 
ing  of  the  walking  on  a  level  and 
the  usual  fall  in  the  pulse-rate 
when  the  "grade  walking  ceased 
at  the  end  of  the  experiment. 
In  curve  A  the  pulse-rate  after 
the  walking  ceased  reached 
more  nearly  the  initial  level 
than  in  curve  B,  but  as  the 
observations  were  continued 
only  7  minutes  after  the  walk- 
ing ceased,  no  information  could 
be  gained  as  to  how  long  a  period  elapsed  before  the  pulse  returned 
to  normal.  In  the  curves  hi  figures  31  and  32,  showing  the  rate 
after  severe  exercise,  the  pulse  was  still  above  the  normal  after  5 

'It  should  be  noted  that  the  arrow  indicates  the  time  of  the  change  and  not  the  pulse-rate.  For 
instance,  in  fig.  31,  curve  A  makes  direct  connection  between  the  two  readings  at  9h  31m  and 
8b  43m  a.  m. ;  the  walking  began  at  9h  42m  a.  m.  If  the  arrow  were  taken  to  indicate  the  pulse- 
rate  at  this  time,  the  rate  would  appear  to  be  142.  On  the  contrary,  it  was  probably  more  nearly 
66  to  68,  and  the  curve  for  the  rise  due  to  the  activity  of  walking  is  actually  much  steeper  than 
here  drawn. 


160 

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Fio.  31. — Typical  pulse  curves  of  E.  D.  B., 
with  subject  standing  and  walking  on  an 
incline.  (Values  per  minute.) 

2,  subject  standing;  3,  walking  on  an  incline. 
Black  points,  records  during  experimental 
periods;  open  circles,  records  between 
periods.  Curve  A,  Feb.  12;  B,  Feb.  14, 
1916. 


PHYSIOLOGICAL   CHANGES   IN   TRANSITION. 


267 


60 


to  7  minutes,  but  here  again  the  records  were  not  continued  a  sufficient 
length  of  tune  to  determine  whether  the  pulse-rate  returned  to  the 
normal  value  or  remained  at  a  higher  rate  for  some  hours,  as  was 
observed  by  Benedict  and  Cathcart.1 

Curve  A  hi  figure  31  shows  a  rise  from  an  average  rate  of  64  to  a  rate 
of  146  when  the  subject  began  to  walk  on  a  30  per  cent  grade.  When 
he  stopped  walking  at  the  end  of  the  first  period,  there  was  an  immediate 
drop  of  53  beats.  When  the  walking  began  again,  the  pulse-rate  rose 
to  170,  with  a  greater  fall  at  the  end  of  the  second  period  of  walking  and 
a  still  greater  rise  for  the  third  period  of  walking.  Curve  B  in  figure  31 
shows  essentially  the  same  characteristics  as  those  of  curve  A  in  the 
same  figure. 


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160 
140 
120 
100 

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Fio.  32.  —  Typical  pulse  curves  of  E.  D.  B.,  with  subject  standing,  and  walking  on  an  incline. 

(Values  per  minute.) 
1  ,  aubj  ect  sitting  ;  2,  standing  ;  3,  walking  on  an  incline.     Black  points,  records  during  experimental 

periods;  open  circles,  records  between  periods.     Curve  A,  Feb.  16;  B,  Feb.  18;  C,  Feb.  17; 

D,  Feb.  19;  E,  Feb.  22;  F,  Feb.  21,  1916. 

In  figure  32  curves  A  and  B  represent  pulse  records  obtained  when 
the  walking  was  continuous  and  illustrate  the  gradual  rise  in  the  pulse- 
rate  due  to  the  cumulative  effect  of  the  exercise.  As  no  records 
of  the  pulse-rate  were  made  in  the  intervals  between  the  walking  periods 
in  the  other  experiments  in  figure  32,  there  is  accordingly  no  picture 
of  the  fall  which  took  place  while  the  subject  was  standing  in  these 
intervals.  (See  C,  D,  E,  and  F.)  The  curves  in  other  respects  are 
similar  to  those  previously  discussed,  and  show  increases  in  the  pulse- 


'Benedict  and  Cathcart,  Carnegie  Inst.  Wash.  Pub.  No.  187,  1913,  p.  154. 


268  METABOLISM   DURING   WALKING. 

rates  of  60  to  80  beats  or  more  in  the  first  period  of  walking.  Curve  E 
represents  the  records  for  the  day  on  which  E.  D.  B.  performed  the 
maximum  amount  of  work  (February  22),  which  was  accompanied  by 
the  maximum  pulse-rate  and  the  maximum  oxygen  consumption.  In 
this  experiment,  also,  no  records  were  made  during  the  intervals  be- 
tween the  periods.  As  will  be  seen,  the  severe  exercise  in  the  walking  •: 
periods  increased  the  pulse-rate  per  minute  over  100  beats. 

BODT-TEMPERATTJRE  DURING  GRADE  WALKING. 

The  measurements  of  the  body-temperature  of  E.  D.  B.  during  grade 
walking  were  begun  on  January  5,  1916,  and  are  given  in  table  16a, 
page  88.  These  temperature  records  were  made  with  a  resistance  ther- 
mometer placed  in  the  rectum  (see  p.  36),  and  represent  average  values. 
It  must  be  understood  that  identical  conditions  did  not  prevail  for  all 
experiments.  These  differences  in  the  conditions,  such  as  in  the  length 
of  preliminary  walking,  the  position  of  the  subject  between  the  periods, 
i.  e.,  sitting,  standing,  or  walking,  and  the  difficulties  which  sometimes 
developed  due  to  the  displacement  of  the  thermometer  as  the  subject 
walked  or  changed  from  standing  or  sitting  to  walking  or  the  reverse, 
all  tend  to  make  direct  comparisons  difficult.  Each  record  must  there- 
fore be  considered  for  the  most  part  by  itself.  This  can  best  be  done 
by  a  series  of  curves. 

In  table  16a  the  data  indicate  a  temperature  rise  between  most  of  the 
periods.  When  this  did  not  occur,  the  cause  may  generally  be  found 
in  the  fact  that  the  subject  rested  in  these  intervals  and  there  was 
accordingly  no  cumulative  effect  of  work.  This  rise  in  tempera- 
ture can  not  be  due  to  the  diurnal  variation  which  is  known  to  exist, 
for  the  periods  are  too  brief  and  as  a  rule  the  differences  between 
succeeding  periods  were  from  0.1°  to  0.3°  C.  Differences  of  over 
1°  C.  are  occasionally  found,  which  may  be  due  to  the  cumulative 
effect  of  work.  On  March  4  there  was  a  fall  of  1°  C.  between  the  sec- 
ond and  third  periods.  The  subject  was  sitting  in  the  interval  between 
these  periods  and  the  temperature  fell  continuously  during  that  time. 
It  continued  to  fall  for  several  minutes  after  the  walking  in  the  third 
period  began  and  remained  at  the  lower  level  during  the  walking  in  the 
fourth  period.  Evidently  the  technique  was  at  fault  on  this  date, 
although  no  mention  is  made  in  the  protocols  of  any  difficulty. 

Temperature  records  taken  on  14  different  days  are  given  in  figures 
33  to  37.  The  tunes  of  change  from  sitting  to  standing  or  standing  to 
walking  or  the  reverse  are  indicated  by  arrows  and  the  usual  numeral 
designations,  i.  e.,  1,  sitting;  2,  standing;  3,  walking  on  an  incline.  As 
in  the  pulse  curves,  the  black  points  represent  records  taken  during  the 
experimental  periods,  and  the  open  circles  the  records  between  the 
periods.  Although  all  of  the  body-temperature  material  for  these  14 
days  have  been  plotted  in  the  curves,  it  does  not  seem  necessary  to 


PHYSIOLOGICAL   EFFECTS  OF   GRADE   WALKING. 


269 


reproduce  the  records  for  the  other  days.  The  data  graphically  given 
were  selected  with  a  view  to  showing  the  body-temperature  with  a 
variety  of  grades  and  speeds  of  walking,  and  the  response  of  the  tem- 
perature record  to  the  changes  from  rest  to  work  and  the  reverse. 
During  the  experiments  on  these  days  the  room  temperature  was, 
on  the  average,  about  21°  C.,  varying  not  more  than  2°  or  3°  C.  from 
this  in  any  experiment. 


37.20 
37.00 
36.80 
36.60 

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FIQ.  33. — Typical  body-temperature  curves  of  E.  D.  B.,  with 
subject  standing  and  walking  on  an  incline.  (Values 
per  minute.) 

1,  subject  sitting;  2,  standing;  3,  walking  on  an  incline. 
Black  points,  records  during  experimental  periods;  open 
circles,  records  between  periods.  Curve  A,  Apr.  15;  B, 
Apr.  14;  C,  Apr.  6,  1916. 

In  figure  33  are  three  curves  (April  15,  14,  and  6)  for  periods  with 
the  subject  in  the  standing  position,  also  walking  with  grades  of  2.4,  5, 
and  10  per  cent.  The  temperatures  for  the  standing  position  were 
fairly  constant  until  the  point  when  walking  began,  which  is  indicated 
by  the  arrow  and  the  numeral  3.1  The  rise  in  the  temperature  curve 

JThe  curves  are  drawn  by  connecting  the  points  for  the  consecutive  readings.  The  locations 
of  the  numbers  and  arrows  for  change  in  position  refer  to  the  approximate  time  and  not  to  the 
temperature. 


270  METABOLISM   DURING   WALKING. 

with  the  change  to  walking  on  these  three  days  is  not  large  in  compari- 
son with  that  shown  in  subsequent  figures,  the  records  in  figure  33 
being  chosen  for  low  grades  and  speeds.  This  increase  does  not  become 
apparent  for  approximately  10  to  15  minutes  after  the  walking  began, 
and  the  rate  of  increase  is  relatively  gradual.  In  the  first  two  curves, 
A  and  B,  there  is  usually  no  noticeable  fall  in  temperature  when,  as  in 
both  experiments,  the  subject  sat  down  at  the  close  of  the  walking 
periods.  In  the  curve  for  the  10  per  cent  grade  (curve  C),  a  more  rapid 
rise  in  temperature  is  evident,  with  a  tendency  to  a  decrease  between 
the  periods.  This  is  apparent,  also,  after  the  second  walking  period 
with  the  5  per  cent  grade  in  curve  B,  when  the  temperature  during 
walking  had  reached  37.46°  C.  The  curve  for  the  10  per  cent  grade 
(curve  C)  shows  a  sudden  fall  in  temperature  following  the  change  to 
walking  before  the  heat  due  to  the  exercise  becomes  noticeable.  This 
was  possibly  owing  to  change  in  resistance  of  the  leads  when  the  sub- 
ject removed  the  blanket  (see  p.  37),  or  possibly  to  some  change  in  the 
position  of  the  thermometer  itself. 

In  figure  34  are  three  different  types  of  curves  (February  2  and  25  and 
March  8).  Here  the  grades  were  25  and  30  per  cent,  with  speeds  from 
46  to  60  meters  per  minute.  The  curves  all  show  an  immediate  rise  in 
temperature  as  soon  as  walking  began,  the  response  being  within 
2  or  3  minutes.  This  is  in  contrast  to  the  curves  in  figure  33.  The 
rise  in  temperature  in  curve  B  was  1.23°  C.  during  28  minutes  of  walk- 
ing, with  a  maximum  of  38.30°  C.  With  the  same  grade,  but  a  speed 
of  51  meters,  the  increase  in  three  periods  of  walking  was  1.45°,  1.49°, 
and  1.52°  C.,  respectively.  (See  carve  C.)  As  soon  as  the  walking 
stopped  and  the  subject  sat  down,  the  temperature  fell  as  rapidly  as  it 
rose  and  in  approximately  40  minutes  had  reached  the  original  level. 
The  effect  of  difference  in  position  may  be  seen  by  the  fact  that  the  fall 
at  the  end  of  the  periods  was  greater  and  more  rapid  in  curve  C,  when 
the  subject  sat  down  with  the  cessation  of  walking,  than  in  curve  B, 
when  the  subject  stood  in  the  intervals  between  the  walking  periods. 
In  the  last  period  in  curve  B  the  walking  was  stopped,  although  the 
measurement  of  the  metabolism  was  continued  somewhat  longer. 
While  the  rise  in  temperature  ceased  and  the  records  almost  imme- 
diately showed  a  level  when  the  walking  stopped,  the  fall  in  temperature 
in  this  case  did  not  occur  until  the  close  of  the  period.  Curve  A  in 
this  figure  shows  a  record  for  an  experiment  in  which  but  three  observa- 
tions were  taken  during  each  period.  In  this  experiment  the  subject 
sat  down  after  each  period  and  the  temperature  did  not  rise  so  high  nor 
fall  so  abruptly  as  hi  curve  C,  hi  which  the  grade  and  speed  were  greater 
and  the  walking  was  continued  through  two  periods  and  the  corre- 
sponding interval  before  the  subject  sat  down. 

In  figure  35  are  four  curves  (February  29,  22,  17,  and  18)  of  the  tem- 
perature changes  when  E.  D.  B.  was  walking  with  a  speed  of  68  to  50 


PHYSIOLOGICAL   EFFECTS   OF   GRADE   WALKING. 


271 


meters  per  minute  (2.5  to  2  miles  an  hour)  on  a  30  to  40  per  cent  grade, 
and  performing  approximately  1,200  to  1,600  kg.  m.  of  work.  With 
a  grade  of  30  per  cent  and  a  speed  of  68  meters  per  minute,  the  body- 
temperature  increased  regularly  during  the  32  minutes  of  continuous 
walking,  reaching  a  maximum  of  38.23°  C.,  with  a  total  rise  of  1.63°  C. 
(See  curve  A.)  The  fall  in  temperature  when  the  subject  stopped 


37.80 
37.60 
37.40 
37.20 
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FIG.  34. — Typical  body-temperature  curves  of  E.  D.  B.,  with  subject  standing,  and  walking  on  an 

incline.  (Values  per  minute.) 

1,  subject  sitting;  2,  standing;  3,  walking  on  an  incline.  Black  points,  records  during  experi- 
mental periods;  open  circles,  records  between  periods.  Curve  A,  Feb.  2;  B,  Feb.  25;  C, 
Mar.  8,  1916. 

walking  and  stood,  at  10h  55m  a.  m.,  was  not  so  rapid  as  that  shown  by 
the  curve  D  when  a  higher  body-temperature  was  reached,  or  when 
the  subject  sat  after  walking,  as  shown  by  curve  C  in  figure  34.  A 
more  rapid  fall  began  at  llh  40™  a.  m.,  when  the  subject  sat  down, 
which  again  was  retarded  during  the  standing  period  of  20  minutes 
about  12  o'clock.  At  1  p.  m.,  after  2  hours  and  5  minutes  of  inter- 
mittent standing  and  sitting,  the  temperature  had  not  reached  the 
initial  level. 


METABOLISM   DURING   WALKING. 


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FIG.  35. — Typical  body-temperature  curves  of  E.  D.  B.,  with  subject  standing,  and  walking  on 'an 

incline.  (Values  per  minute.) 

1,  subject  sitting;  2,  standing;  3,  walking  on  an  incline.  Black  points,  records  during  experi- 
mental periods;  open  circles,  records  between  periods.  Curve  A,  Feb.  29;  B,  Feb.  22-  C, 
Feb.  17;  D,  Feb.  18,  1916. 

Curve  C  gives  the  body-temperature  for  the  experiment  of  February 
17,  when  there  was  an  initial  period  of  standing  followed  by  several 
periods  when  the  subject  walked  on  a  35  per  cent  grade  at  a  speed  of 
62  meters  per  minute.  The  subject  stood  after  each  walking  period. 
In  the  first  19  minutes  of  walking  the  temperature  rose  0.82°  C.,  i.  e., 
at  the  rate  of  0.04°  C.  per  minute.  The  total  effect  of  the  exercise  was 
an  increase  in  the  body-temperature  of  approximately  1.7°  C.,  with  a 
maximum  body-temperature  of  38.80°  C. 


PHYSIOLOGICAL   EFFECTS   OF   GRADE   WALKING.  273 

In  curve  D  a  graphic  record  is  given  of  the  body-temperature  found 
in  the  experiment  of  February  18,  with  E.  D.  B.  walking  at  an  average 
rate  of  50  meters  per  minute  on  a  40  per  cent  grade.  Here,  also,  the 
walking  was  preceded  by  a  period  of  standing,  with  practically  the  same 
body-temperature  at  the  beginning  as  in  curve  C.  In  contrast  to 
February  17,  the  rise  in  the  first  19  minutes  of  walking  was  but  0.66°  C., 
or  0.03°  C.  per  minute.  The  slope  of  the  curve  for  the  grade  walking 
is  practically  constant  up  to  38.50°  C.,  and  thereafter  the  rate  of  in- 
crease diminishes.  Although  the  grade  was  5  per  cent  greater  on 
February  18  than  it  was  on  February  17,  a  decrease  in  speed  of  12  me- 
ters per  minute  resulted  in  a  smaller  amount  of  work  on  this  day 
(1,188  kg.  m.  as  compared  with  1,306  kg.  m.  on  February  17),  which 
was  sufficient  to  retard  the  rise  in  the  body-temperature.  In  this 
experiment  there  was  continuous  walking  from  9h  25m  to  10h  35m  a.  m. 
(1  hour  and  10  minutes),  with  a  total  increase  in  temperature  of  1.96°  C. 
and  a  maximum  temperature  of  39. 10°  C.  The  subject  was  much  out  of 
breath  when  he  stopped  walking  and  was  sweating  freely.  As  stated 
earlier,  the  electric  fan  was  not  used  for  cooling  during  the  experi- 
ments with  E.  D.  B.  (See  p.  37.) 

Curve  B  in  figure  35,  which  gives  records  for  the  experiment  on  Feb- 
ruary 22,  when  the  grade  was  40  per  cent  and  the  speed  65  meters  per 
minute,  represents  the  temperature  on  the  day  when  E.  D.  B.  did  his 
maximum  amount  of  work  of  1,569  kg.  m.  per  minute  with  an  oxygen 
consumption  of  3,132  c.  c.  per  minute,  and  a  total  heat-output  per 
minute  of  15.65  calories.  Although  the  maximum  body-temperature 
was  not  so  great  as  that  shown  in  curve  D,  when  the  walking  was  con- 
tinuous for  1  hour  and  10  minutes,  yet  the  increment  during  walking 
is  shown  by  curve  B  to  have  been  1.62°  C.  in  23  minutes.  This  was  an 
increase  at  the  rate  of  0.07°  C.  per  minute.  The  rate  of  increase  is 
thus  larger  than  that  shown  in  curves  C  and  D  when  the  temperature 
rose  0.04°  and  0.03°  C.  per  minute,  respectively,  and  the  work  performed 
was  less.  It  may  reasonably  be  said,  therefore,  that  for  amounts  of 
work  over  1,000  kg.  m.  per  minute,  the  body-temperature  may  increase 
from  0.03°  to  0.07°  C.  per  minute  for  the  first  10  to  20  minutes,  with  a 
maximum  total  increase  of  1.5°  to  2.0°  C. 

The  curves  hi  figure  36  (February  26  and  15)  are  included  to  show 
more  especially  the  fall  in  the  body-temperature  after  the  walking 
stopped.  In  the  experiment  of  February  26  (curve  A)  the  grade  was 
30  per  cent  and  the  speed  70  meters  per  minute.  The  walking  ceased 
at  10b  32m  a.  m.,  and  in  the  subsequent  period  of  2  hours  and  3  minutes, 
during  which  the  man  alternately  stood  and  sat,  the  body-temperature 
fell  1.58°  C.  This  fall  brought  the  body-temperature  below  the  level 
in  the  first  standing  period  of  the  forenoon. 

In  the  experiment  on  February  15  the  grade  was  35  per  cent  and  the 
speed  was  45  meters  per  minute.  When  the  walking  ceased  at  llh  7m 


274 


METABOLISM   DURING   WALKING. 


a.  m.,  the  body-temperature  decreased  rapidly,  the  fall  amounting  to 
1.14°  C.  in  12  minutes,  or  0.09°  C.  per  minute.  Unless  the  technique 
was  at  fault,  which  has  not  been  revealed  by  a  careful  inspection  of  the 
records,  this  change  in  temperature  of  the  body  in  cooling  is  by  far  the 
greatest  and  most  rapid  we  have  found.  A  possible  explanation,  but  one 
for  which  our  records  give  no  data,  is  that  the  subject  stood  without 
the  usual  blanket  covering.  In  this  case,  with  the  thin,  short-sleeved, 
and  short-legged  athletic  suit  worn  by  the  man,  the  radiation  would 
be  greatly  increased.  The  curve  would  thus  indicate  that  the  un- 
restricted liberation  of  heat  from  the  body  can  be  as  rapid  as  the  sudden 
production  of  heat  following  the  beginning  of  muscular  exercise. 


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Fio.  36. — Typical  body-temperature  curves  of  E.  D.  B.,  with  subject  standing, 

and  walking  on  an  incline.     (Values  per  minute.) 
1,  subject  sitting;  2,  standing;  3,  walking  on  an  incline.     Black  points,  records 

during  experimental  periods;  open  circles,  records  between  periods. 

Figure  37  (a  grouping  of  curves  for  February  18  and  22,  March  23, 
and  April  8)  gives  four  contrasting  curves  showing  typical  changes  in 
body-temperature.  The  curves  for  the  experiments  with  a  40  per  cent 
grade  (February  18  and  22)  have  already  been  shown  in  curves  D  and 
B  in  figure  35.  These  are  in  strong  contrast  to  the  curves  for  the 
experiments  of  April  8  and  March  23,  in  which  the  grades  were  10  per 
cent  and  the  speed  of  walking  36  and  62  meters  per  minute,  respectively. 
The  lowest  curve  of  the  four  (that  for  April  8,  when  the  smallest  amount 
of  work  was  done)  shows  that  the  rise  in  temperature  was  not  large 
and  that  the  fall  between  the  periods  was  slight.  Apparently,  at  the 
close  of  the  last  period,  the  rise  in  temperature  was  approaching  a  limit. 
The  curve  for  the  other  experiment  with  a  10  per  cent  grade  (March  23) 
indicates  a  more  rapid  increase  in  temperature,  with  a  more  decided 
fall  between  the  periods.  There  is  no  evidence  that  the  rise  had  reached 
its  limit  when  the  experiment  ceased.  The  two  curves  with  steeper 
grade  (40  per  cent)  show  similar  characteristics,  but  in  greater  degree. 


PHYSIOLOGICAL   EFFECTS   OF   GRADE   WALKING. 


275 


The  average  body-temperature  is  of  special  interest  in  experiments 
in  which  the  energy  changes  are  determined  by  direct  calorimetry  and 
in  which  an  accumulation  of  heat  hi  the  body  escapes  direct  measure- 
ment. The  temperatures  as  here  reported  may  not  be  considered  as 
representing  the  average  values  for  the  whole  body,  for,  as  has  been 
stated  in  earlier  publications,1  the  temperature  of  the  body  as  a  whole 
has  a  wide  range.  The  data  given  here  represent  the  temperature  of 
the  rectum  only.  If,  however,  we  accept  these  values  as  repre- 
senting the  body  average,  we  see  that  the  temperature  may  be  increased 
from  1  to  2  degrees,  which,  with  a  body-weight  of  60  kg.  and  an  assumed 


FIQ.  37. — Contrasting  curves  of  body-temperature  of  E.  D.  B.,  with 
subject  standing  and  walking  on  an  incline.  (Values  per  minute.) 

1,  subject  sitting;  2,  standing;  3,  walking  on  an  incline.  Black  points, 
records  during  experimental  periods;  open  circles,  records  be- 
tween periods. 

specific  heat  of  0.83°  C.,  results  hi  a  storage  of  100  calories  of  heat  in 
the  body,  for  which  allowance  must  be  made  in  all  studies  by  direct 
calorimetry.  Since,  however,  the  amount  of  heat  stored  in  the  body 
is  dependent  on  so  many  conditions,  such  as  clothing,  air-currents,  and 
intensity  of  work,  only  direct  measurements  of  the  body-temperature 
hi  each  instance  can  be  relied  upon  to  give  this  value.  It  should  be 
noted  that  we  used  no  electric  fan  or  other  artificial  means  (see  p.  37) 
for  keeping  the  subject  cool  during  the  experiments,  and  the  changes 

Benedict  and  Snell,  Arch.  f.  d.  ges.  Physiol.,  1901,  88,  p.  492;  also,  Benedict  and  Slack,  Car- 
negie Inst.  Wash.  Pub.  No.  155,  1911. 


METABOLISM   DURING   WALKING. 


are  those  due  to  natural  radiation  and  convection  as  affected  by  the 
very  light-weight  clothing  which  the  subject  wore  at  the  tune. 

Although  the  temperatures  obtained  in  this  study  do  not  show  equal 
increases  for  similar  amounts  of  work  on  different  days,  yet  a  higher 
temperature  and  a  greater  increase  over  the  normal  temperatures  dur- 
ing standing  were  usually  observed  when  the  work  and  the  metabolism 
were  greatest.  As  was  found  with  the  pulse-rate,  there  is  evidently 
a  general  relation  between  the  amount  of  work  and  body-temperature. 

BLOOD-PRESSURE  DURING  GRADE  WALKING. 

The  few  readings  of  the  blood-pressure  of  E.  D.  B.  were  made  when 
but  small  amounts  of  work  were  done.  Consequently  the  effect  of 
work  on  the  blood-pressure  was  not  large.  As  previously  stated,  these 
readings  were  of  the  systolic  pressure  only,  and  were  made  with  the 
subject  standing  after  a  preliminary  walking  period  and  again  just 
after  the  experimental  period  closed.  The  results  of  these  measure- 
ments, which  comprise  those  for  7  days  with  grade  walking,  are  given 
in  table  16a,  page  88. 

TABLE  80. — Blood-pressure  of  E.  D.  B.  during  grade  walking  in  experiments  without  food. 

(Values  per  minute.) 


Blood-pressure  during  — 

Increase  in 

Amount  of 

Standing. 

Walking. 

due  to  walking. 

in  walking. 

1916. 

mm. 

mm. 

mm. 

kg.  m. 

Mar.  23. 

114 

118 

4 

380 

24. 

120 

127 

7 

310 

Apr.     6  . 

116 

126 

10 

284 

7. 

119 

130 

11 

281 

8. 

125 

139 

14- 

223 

14. 

116 

128 

12 

126 

15. 

118 

128 

10 

59 

Excepting  for  the  first  period  of  April  6,  the  records  show  close  agree- 
ment for  the  periods  of  the  same  day,  with  a  slight  tendency  to  increase 
during  the  forenoon.  The  blood-pressure  increased  over  the  standing 
values  hi  all  instances,  as  may  be  seen  from  table  80,  in  which  both 
these  values  and  the  kilogrammeters  of  work  done  are  given.  The 
range  of  increase  was  from  4  to  14  mm.,  with  an  average  value  of  10 
mm.  The  blood-pressure  for  the  walking  period  of  March  23  is  proba- 
bly too  low,  as  there  was  a  lapse  of  2  minutes  after  the  walking  ceased 
before  the  pressure  was  read. 

There  appears  to  be  no  indication  in  these  figures  of  direct  connection 
between  the  amount  of  work  performed  and  the  blood-pressure,  but 
up  to  a  certain  point  it  appears  that  the  increase  in  the  blood-pres- 
sure found  during  grade  walking  over  the  values  obtained  with  the 
subject  standing  is  inversely  proportional  to  the  amount  of  work 


PHYSIOLOGICAL   CHANGES  IN   TRANSITION.  277 

done.  This  can  hardly  be  regarded  as  significant,  and  the  probable 
explanation  lies  in  the  technique,  for,  though  the  procedure  was  uni- 
form, there  was  probably  a  variation  of  10  to  15  seconds  between  the 
cessation  of  work  and  the  time  of  reading  the  pressure.  Cotton,  Rap- 
port, and  Lewis1  have  shown  that  the  blood-pressure  changes  rapidly  on 
cessation  of  exercise,  rising  abruptly  for  the  first  20  to  60  seconds  and 
then  falling  to  normal  in  from  1  to  4  minutes.  With  such  small  differ- 
ences in  the  blood-pressure  as  here  reported,  any  error  in  the  time  of 
reading  would  account  for  this  lack  of  uniformity  between  the  work 
and  the  increase  in  the  blood-pressure. 

The  values  found  are  similar  in  degree  to  those  obtained  for  the  same 
subject  when  he  was  walking  on  a  level  (see  table  11  a,  p.  67),  though 
the  increases  over  the  standing  values  are  here  a  trifle  higher  on  the 
whole.  It  is  evident  that  these  measurements  do  not  cover  a  suffi- 
ciently wide  range  of  work  to  warrant  an  estimate  of  the  effects  of 
grade  walking  upon  the  blood-pressure,  other  than  to  note  an  approxi- 
mate increase  of  10  mm.  in  blood-pressure  when  the  work  was  300  kg.  m. 
or  less.  This  increase  corresponds  roughly  to  an  average  increase  in  the 
oxygen  consumption  of  500  c.  c.  per  minute,2  or  9  c.  c.  per  kilogram  of 
body-weight,  which  is  of  the  same  range  as  that  found  in  the  experi- 
ments with  level  walking.  Liljestrand  and  Stenstrom3  with  the  sub- 
ject N.  S.  during  level  walking  found  an  oxygen  increase  of  850  c.  c. 
for  a  rise  of  10  mm.  in  blood-pressure,  while  for  the  much  lighter  sub- 
ject G.  L.  the  increase  in  the  oxygen  consumption  was  650  c.  c.  for  an 
increase  of  8  mm.  in  blood-pressure.  These  increases  would  correspond 
to  an  increase  in  the  oxygen  consumption  of  8  and  10  c.  c.  per  kilogram 
of  body-weight. 

PHYSIOLOGICAL  CHANGES  IN  TRANSITION  FROM  STANDING  TO  GRADE  WALKING 

AND  THE  REVERSE. 

It  is  of  importance  to  find  out,  if  possible,  how  quickly  the  body  re- 
sponds to  the  demands  made  upon  it  when  varying  amounts  of  muscu- 
lar work  are  done  and  how  soon  it  may  be  said  that  the  body  has 
adapted  itself  to  the  new  conditions,  for  the  comparison  of  the  results 
obtained  hi  this  research  presupposes  that  the  metabolism  has  not 
suffered  any  change  in  degree  within  the  daily  experimental  period  and 
that  a  sufficient  period  of  exercise  has  been  allowed  before  the  beginning 
of  each  day's  observations  for  the  bodily  functions  to  become  settled. 
It  is,  furthermore,  important  to  determine  how  long  the  effects  of  mus- 
cular work  are  present  after  the  subject  is  again  at  rest.  Observations 
were  accordingly  made  in  the  grade- walking  experiments  of  the  changes 
in  the  rates  of  respiration,  pulmonary  ventilation,  oxygen  consumption, 
and  pulse  during  the  transition  from  standing  to  walking  and  from 
walking  to  standing. 

Cotton,  Rapport,  and  Lewis,  Heart,  1917,  6,  p.  269.  2See  table  59,  p.  229. 

'Liljestrand  and  Stenstrom,  Skand.  Arch.  f.  Physiol.,  1920,  39,  p.  211. 


278 


METABOLISM   DURING   WALKING. 


The  data  for  the  transitional  changes  in  the  respiration,  pulmonary 
ventilation,  and  oxygen  consumption  were  secured  by  employing  the 
records  of  the  kymograph  according  to  the  methods  already  described 
hi  giving  the  results  of  the  study  on  the  effect  of  the  mouthpiece  upon 
the  same  factors.  (See  p.  182.)  A  reproduction  of  two  typical  kymo- 
graph records  obtained  in  these  transition  periods  is  given  in  figure  38. 
The  lower  record  (A)  represents  the  change  from  standing  to  grade 
walking,  and  the  upper  record  (B)  the  change  from  grade  walking  to 
standing.  The  exact  point  when  the  change  occurred  is  indicated 


FIG.  38. — Typical  kymograph  records  of  respiration,  pulmonary  ventilation,  and 
rate  of  oxygen  consumption  in  periods  of  transition  from  standing  to  walk- 
ing and  the  reverse. 

A,  standing  to  walking.  B,  walking  to  standing.  The  arrows  indicate  the  exact 
point  when  change  occurred.  Records  of  time  and  pulmonary  ventila- 
tion adder  above  each  kymograph  tracing. 

in  both  cases  by  an  arrow.  The  hill-and-valley  effect  due  to  the  re- 
filling of  the  spirometer  with  oxygen,  and  referred  to  on  page  182,  may 
be  noted  in  these  records. 

RESPIRATORY  CHANGES  IN  TRANSITION  FROM  STANDING  TO  GRADE  WALKING. 

The  observations  of  the  changes  due  to  transition  from  standing  to 
grade  walking  were  made  with  the  subject  standing  for  3  or  more 
minutes;  the  treadmill  was  then  started,  and  the  tracings  on  the  kymo- 
graph were  noted  as  the  subject  walked.  The  data  recorded  in  tables 


PHYSIOLOGICAL   CHANGES   IN   TRANSITION.  279 

81  and  82  were  obtained  by  measuring  these  kymograph  records.  The 
length  of  time  the  subject  had  been  standing  previous  to  these  transi- 
tion observations  varied  considerably,  the  range  being  10  to  50  minutes. 
As  the  condition  in  the  transitional  periods  varied  widely,  averaging 
the  values,  as  was  done  in  the  regular  series  of  experiments,  would  give 
results  without  significance.  The  results  of  each  period  have  therefore 
been  grouped  separately  and  the  measurements  of  the  respiration, 
ventilation,  and  oxygen  consumption  for  fractions  of  a  minute  have 
been  tabulated  on  the  per  minute  basis.  The  data  for  pulmonary 
ventilation  and  oxygen  consumption,  as  given  in  tables  81  and  82,  have 
not  been  corrected  for  the  temperature  changes,  as  they  are  intended 
for  approximate  comparison  only. 

CHANGES  IN  RESPIRATION-KATE. 

The  data  for  the  respiration-rate  are  given  in  table  81.  The  respira- 
tions during  the  standing  before  walking  were  measured  from  the 
kymograph  curve  for  full  minutes,  no  measurements  being  made  of  the 
respiration  during  the  last  minute  of  standing,  when  the  blanket  was 
removed  from  the  subject  before  he  began  walking.  During  the  first 
minute  of  walking  each  measurement  covered  approximately  12  seconds 
and  hi  the  succeeding  minutes  15  seconds.  As  given  in  the  table, 
however,  the  respirations  for  these  fractions  of  a  minute  have  been 
computed  to  a  per  minute  rate. 

By  inspecting  the  figures  in  table  81,  it  will  be  seen  that  the  respira- 
tion-rate for  standing  was  fairly  uniform  during  the  tune  of  measure- 
ment, the  changes  from  period  to  period  being  slight  and  thus  in  keep- 
ing with  the  measurements  in  the  standing  experiments  previously 
discussed.  (See  p.  101.)  This  gives  evidence  that  the  respiration-rate 
had  returned  to  its  normal  standing  value  following  the  walking  of  the 
preceding  period.  In  the  majority  of  the  periods  the  increase  in  the 
respiration-rate  for  the  first  one-fifth  minute  of  walking  was  at  the  rate 
of  from  8  to  10  respirations  per  minute,  or,  in  round  numbers,  an  in- 
crease of  50  per  cent  over  the  standing  rate.  During  the  following  frac- 
tion of  the  first  minute  there  was,  on  the  whole,  a  tendency  to  a  further 
increase  at  the  rate  of  1  to  3  respirations  per  minute,  though  in  a  few 
instances  there  was  a  fall.  The  major  portion  of  the  increase  occurred 
within  the  first  12  seconds.  In  the  following  minutes,  measured  in 
15-second  intervals,  the  rates  were,  as  a  rule,  higher  as  the  time  ad- 
vanced, and  though  there  are  periods  when  constancy  was  apparently 
reached  by  the  second  minute  (see  second  period  of  March  9,  fourth 
period  of  March  15,  and  second,  third,  and  fourth  periods  of  March  17), 
there  are  others  (March  16  and  February  24)  which  show  gams  through- 
out the  record.  The  change  in  the  rate  due  to  transition  from  standing 
to  walking,  except  with  severe  grades  (see  March  16  and  February  24), 
may  be  said  to  occur,  however,  in  the  first  minute,  and  the  most  of 
the  change  is  in  the  first  12  seconds. 


280 


METABOLISM   DURING   WALKING. 


TABLE  81. — Respiration-rate  and  pulmonary  ventilation  of  E.  D.  B.  in  periods  of  transition  from  standing 

to  grade  walking.     (Values  per  minute.) 


Date,  condition,  and  period  of 
measurement. 

Period  I. 

Period  II. 

Period  III. 

Period  IV. 

Respi- 
ration- 
rate. 

Pul- 
monary 
venti- 
lation 
(unre- 
duced) 

Respi- 
ration- 
rate. 

Pul- 
monary 
venti- 
lation 
(unre- 
duced) 

Respi- 
ration- 
rate. 

Pul- 
monary 
venti- 
lation 
(unre- 
duced) 

Respi- 
ration- 
rate. 

Pul- 
monary 
venti- 
lation 
(unre- 
duced] 

March  9,  1916. 
Standing  measured  in  minutes  

16.3 
16.3 
16.6 

liters. 
10.6 
10.9 
11.5 

16.5 

16.8 
16.2 

liters. 
11.3 
11.3 
11.6 

17.0 
16.2 
17.3 

liters. 
11.5 
10.6 
11.6 

15.5 
15.4 
17.3 

liters. 
10.7 
10.8 
11.6 

Walking,  30  p.  ct.;  av.,  49.6  meters: 
Measured  in  1/5  min.: 
1st  

20.8 
22.5 
24.3 
25.7 
27.9 

25.2 
25.5 
31.6 
42.6 
47.6 

26.2 
23.9 
25.0 
25.0 
24.1 

24.1 
27.8 
36.0 
42.5 
44.4 

25.8 
23.5 
23.5 
24.8 
29.1 

27.3 
29.6 
32.6 
44.1 
51.0 

25.0 
24.0 
21.8 
24.0 
25.7 

23.6 
28.6 
33.4 
42.1 
46.2 

2d  

3d  

4th  

5th  

Following  1/4  min.  : 
1st  

25.4 
25.0 
23.9 
22.7 

44.0 
46.0 
49.5 
49.8 

29.9 
28.0 
24.0 
22.5 

57.0 
55.5 
51.9 
40.7 

27.4 

27.4 
29.1 
25.8 

52.5 
61.6 
58.4 
44.8 

29.0 
30.0 
28.0 
27.8 

57.9 
64.5 
63.7 
54.3 

2d  

3d  

4th  

5th  

24.8 
27.1 
26.0 
27.0 

43.1 
44.1 
45.1 
47.2 

25.9 
24.4 
25.1 
25.9 

41.9 
43.1 
48.0 
52.9 

28.7 
30.1 
31.3 
30.1 

47.0 
51.2 
56.2 
59.6 

28.6 
29.8 
32.3 
33.4 

51.2 
57.3 
62.9 
69.5 

6th  

7th  

8th  

9th  

29.1 
27.0 

27.7 
28.4 

53.3 
55.3 
61.9 
48.3 

23.4 
23.4 
26.0 
28.8 

53.7 
55.7 
63.4 
55.6 

31.0 

28.4 
27.4 
26.4 

69.1 
59.6 
51.1 

47.5 

28.2 
28.5 
24.8 
29.1 

67.2 
59.3 
52.6 
50.4 

10th  

llth  

12th  

13th  

27.7 
24.9 
28.0 
29.8 

44.2 
47.8 
52.6 
58.3 

26.5 
24.3 
25.3 
26.1 

49.6 
47.8 
54.1 
60.2 

28.9 
32.0 
32.0 
29.3 

52.2 
62.1 
64.0 
68.1 

32.3 
30.0 
30.0 
30.0 

60.2. 
64.9 
68.8 
61.8 

14th  

15th  

16th  

17th  

28.3 
23.7 
23.9 
26.8 

59.0 
55.4 
46.4 
46.5 

28.0 
26.9 
26.9 
26.2 

67.0 
59.5 
48.3 
50.6 

26.6 
28.3 
31.0 
31.0 

51.2 
47.4 
52.9 
56.1 

24.8 
30.0 
28.8 
29.8 

51.5 
55.2 
57.1 
62.6 

18th  

19th  

20th  

21st  

29.3 
27.4 

51.3 
52.4 

26.2 
25.8 

50.4 
55.7 

28.7 
29.8 
31.7 
32.8 

65.9 
59.5 
59.6 
67.9 

22d  

23d  

24th  

March  14,  1916. 
Standing,  measured  in  minutes  

16.2 
15.7 
16.5 
17.2 
16.6 

26.5 
30.2 
24.4 
23.7 
29.3 

10.7 
11.2 
11.7 
11.5 
11.9 

25.2 
32.0 
36.7 
38.7 
45.3 

16.5 
16.8 
17.5 
17.8 

10.9 
11.3 
12.5 
13.7 

17.5 
16.4 
16.5 
17.4 

10.3 
10.5 
10.5 
11.3 

17.2 
17.3 
17.1 
17.6 

11.2 
11.6 
11.1 
11.8 

Walking,  30  p.  ct.;  av.  59.9  meters: 
Measured  in  1/5  min. 
1st  

26.0 
28.3 
27.9 
26.7 
28.0 

24.5 
22.2 
28.0 
35.1 
42.1 

26.6 
26.6 
25.6 
27.3 
25.8 

26.7 
26.3 
33.8 
34.5 
42.2 

26.0 
25.0 
27.9 
27.1 
27.9 

28.7 
32.6 
35.8 
40.5 
43.7 

2d  

3d  

4th  

5th  

PHYSIOLOGICAL   CHANGES   IN   TRANSITION. 


281 


TABLE  81. — Respiration-rate  and  pulmonary  ventilation  of  E.  D.  B.  in  periods  of  transition  from  standing 
to  grade  walking.     (Values  per  minute.) — Continued. 


Date,  condition,  and  period  of 
measurement. 

Period  I. 

Period  II. 

Period  III. 

Period  IV. 

Respi- 
ration- 
rate. 

Pul- 
monary 
venti- 
lation 
(unre- 
duced). 

Respi- 
ration- 
rate. 

Pul- 
monary 
venti- 
lation 
(unre- 
duced.) 

Respi- 
ration - 
rate. 

Pul- 
monary 
venti- 
lation 
(unre- 
duced). 

Respi- 
ration- 
rate. 

Pul- 
monary 
venti- 
lation 
(unre- 
duced). 

March  14,  1916—cont'd. 
Walking,  30  p.  ct.  ;  av.  59.9  meters  —  con. 
Following  1/4  min.: 
1st  

29.4 
25.4 
26.4 
22.6 

liters. 
49.9 
53.3 
55.4 
51.2 

27.6 
28.5 
26.1 
28*6 

liters. 
45.9 
48.9 
51.9 
57.2 

25.8 
26.7 
27.2 
27.6 

liters. 
51.2 
52.7 
57.0 
60.3 

30.2 
27.3 
29.2 
29.2 

liters. 
49.4 
53.1 
61.2 
64.0 

2d  

3d  

4th  

5th  

28.7 
27.5 
31.4 
27.1 

58.7 
56.2 
64.6 
58.2 

30.2 
32.3 

24.8 
26.4 

57.6 
59.0 
53.3 
57.5 

27.0 
27.6 
24.4 
27.6 

64.1 
64.3 
60.4 
64.7 

27.1 
25.7 
28.0 
27.1 

63.3 
59.2 
61.5 
63.2 

6th  

7th  

8th  

9th  

29.0 
25.4 
26.3 
29.4 

59.7 
53.3 
60.3 
60.6 

26.9 
29.7 
29.7 
26.7 

56.0 
61.0 
63.2 
53.8 

31.0 
33.8 
29.7 
29.2 

67.9 
67.0 
64.6 
68.3 

28.9 
29.2 
26.6 
25.5 

64.4 
66.5 
64.4 
64.6 

10th  

llth  

12th  

13th  

29.4 
28.1 

59.2 
58.5 

30.5 
29.6 
27.5 

60.0 
62.2 
62.4 

26.5 
29.2 
28.2 
26.5 

61.1 
68.8 
64.9 
66.1 

29.3 
28.7 
29.4 
29.3 

69.1 
66.8 
65.6 
68.5 

14th  

15th  

16th. 

March  15,  1916. 
Standing,  measured  in  minutes  

16.3 
16.8 
15.5 
15.3 

11.0 
11.2 
10.1 
9.7 

15.0 
16.7 
16.7 
16.7 

10.2 
11.0 
11.3 
11.3 

16.3 
16.9 
16.4 
16.4 

11.7 
11.9 
9.9 
11.5 

16.5 
17.6 
17.4 
16.5 
17.1 

20.9 
19.6 
22.8 
23.5 
29.0 

10.7 
12.8 
11.8 
10.5 
13.0 

Walking,  30  p.  ct.;  av.,  69.6  meters: 
Measured  in  1/5  min.: 
1st  

34.0 
26.3 
28.4 
24.5 
26.6 

32.9 
33.5 
31.4 
41.9 
46.8 

22.3 
21.8 
24.5 
24.7 
25.5 

24.4 
35.2 
31.0 
33.7 
44.9 

24.1 
31.9 
24.1 
26.4 
27.5 

20.9 
29.5 
39.5 
37.4 
48.3 

2d  

30.6 
40.1 
37.1 
50.0 

3d  

4th  

5th  

Following  1/4  min.: 
1st  

28.6 
26.0 
29.9 
27.4 

53.1 

57.8 
64.4 
61.7 

28.8 
29.6 
30.4 
26.2 

52.6 
59.0 
61.9 
61.8 

25.8 
28.6 
30.2 
27.5 

51.3 
60.1 
66.7 
65.9 

28.7 
25.3 
26.7 
28.9 

53.9 
59.7 
66.7 

72.7 

2d  

3d  

4th  

5th  

29.6 
30.1 
31.0 
29.3 

70.0 
75.3 
76.2 
71.9 

25.5 
24.8 
26.5 
29.6 

67.1 
67.4 
66.1 
75.1 

28.4 
28.4 
28.4 
29.1 

71.3 
72.2 
70.1 
76.9 

28.3 
28.7 
28.3 
30.4 

75.9 
74.6 
72.0 
77.3 

6th  

7th  

8th  

9th  

28.3 
26.0 
29.0 
29.0 

69.4 
72.2 
75.9 
70.3 

28.2 
26.3 
26.2 
23.5 

76.7 
68.1 
66.9 
64.4 

31.2 
30.5 
29.4 
26.7 

80.4 
80.2 
72.9 
66.6 

25.3 

28.0 
28.6 
28.3 

75.9 

78.7 
73.9 

75.8 

10th  

llth  

12th  

13th  

31.0 

73.3 

28.9 
30.6 

75.3 
75.0 

24.0 
24.0 

62.9 
67.7 

26.6 
30.3 

74.8 
79.4 

14th  

282 


METABOLISM   DURING   WALKING. 


TABLE  81 Respiration-rate  and  pulmonary  ventilation  of  E.  D.  B.  in  periods  of  transition  from  standing 

to  grade  walking.     (Values  per  minute.) — Continued. 


Date,  condition,  and  period  of 
measurement. 

Period  I. 

Period  II. 

Period  III. 

Period  IV. 

Respi- 
ration- 
rate. 

Pul- 
monary 
venti- 
lation 
(unre- 
duced). 

Respi- 
ration- 
rate. 

Pul- 
monary 
venti- 
lation 
(unre- 
duced). 

Respi- 
ration - 
rate. 

Pul- 
monary 
venti- 
lation 
(unre- 
duced). 

Respi- 
ration- 
rate. 

Pul- 
monary 
venti- 
lation 
(unre- 
duced). 

March  17,  1916. 

14.9 
14.7 
14.1 
13.6 
15.3 

23.8 

liters. 
9.7 
9.9 
10.0 
8.8 
11.2 

16.0 
16.0 
15.6 
16.5 
16.1 

24.0 
24.3 
24.3 
25.2 
25.2 

liters. 
10.3 
10.6 
10.5 
10.5 
10.6 

20.7 
26.9 
29.5 
31.4 
35.2 

16.3 
17.4 
16.6 
17.0 
16.7 

24.0 
24.0 
24.0 
25.4 
24.4 

liters. 
11.0 
11.8 
11.1 
10.3 
13.4 

22.0 
29.5 
29.5 
34.5 
34.6 

17.7 
17.7 
17.7 
16.4 
16.9 

21.7 
26.6 
25.4 
26.6 
27.0 

liters. 
11.2 
11.0 
11.2 
10.9 
10.8 

18.9 
27.7 
26.8 
36.8 
39.9 

Walking,  30  p.  ct.;  av.,  52.9  meters: 
Measured  in  1/5  min.  : 
1st                                   .... 

2d  

26.5 
21.2 
20.2 
23.0 

29.4 
24.7 
29.7 
36.4 

3d  

4th  

5th  

Following  1/4  min.: 
1st  

24.9 
26.5 
26.5 
24.6 

43.6 
47.0 
49.3 
48.2 

26.8 
25.5 
25.5 
26.4 

41.4 
40.8 
42.2 
45.4 

25.2 
25.2 
26.1 
24.7 

40.2 
44.1 
44.1 
43.0 

29.3 
27.1 
25.5 
25.7 

44.7 
45.0 
46.4 
47.9 

2d  

3d  

4th   

6th  

25.8 
23.2 
25.8 
27.1 

52.6 
51.4 
50.7 
50.8 

25.1 
26.6 
24.9 
25.2 

46.2 
47.6 
52.8 
49.3 

24.0 
25.5 
27.1 
26.7 

47.6 
55.5 
56.4 
53.4 

26.3 
25.4 
27.8 
27.8 

51.5 
53.1 
55.6 
53.0 

6th  

7th  

8th  

9th  

25.9 
28.0 
28.9 
24.9 

53.3 
63.4 
56.6 
52.9 

25.7 
27.2 
25.5 
27.2 

47.2 
50.7 
48.0 
51.0 

25.7 
24.0 
28.7 
26.4 

52.5 
51.5 
57.3 
55.7 

26.5 
27.1 
29.1 
26.3 

50.6 
65.0 
67.8 
66.0 

10th  

llth  

12th  

13th  

26.4 
28.0 
26.4 
25.6 

53.1 
59.0 
53.9 
54.1 

27.6 
31.0 
24.9 
25.6 

54.8 
60.8 
50.6 
52.1 

26.4 
26.0 
26.2 
28.0 

55.9 
51.8 
53.1 
55.6 

28.2 
28.1 
26.2 
25.4 

65.2 
56.0 
52.7 
53.4 

14th  

15th  

16th  

17th  

24.7 

53.1 

25.6 
27.2 

61.9 
54.2 

28.0 
28.0 

55.9 
58.6 

27.8 
24.6 

56.3 
55.9 

18th  

March  16,  1918. 
Standing,  measured  in  minutes:  

15.0 
16.1 
15.1 
16.3 
18.0 

27.2 
24.7 
28.7 
26.3 
26.3 

10.2 
8.3 
7.3 
7.6 
12.4 

26.1 
31.7 
33.9 
43.3 
50.3 

15.3 
16.7 
14.0 
15.4 
16.3 

26.7 
28.2 
20.8 
20.0 
19.2 

10.2 
8.1 
6.7 
7.4 
9.8 

25.0 
27.8 
33.9 
39.1 
40.4 

17.0 
16.3 
13.4 
17.8 
18.3 

21.7 
20.9 
24.3 
24.8 
23.4 

9.3 
7.9 
6.3 
7.6 
11.2 

29.1 
32.0 
30.9 
36.8 
37.8 

16.3 
15.9 
16.6 
18.5 

7.8 
8.3 
7.0 
7.7 

Walking,  40  p.  ct.;  av.,  66.1  meters: 
Measured  in  1/5  min.: 
1st  

24.8 
24.0 
26.7 
27.9 
23.1 

32.2 
43.3 
45.2 
43.5 
49.2 

2d  

3d  

4th  

5th  

PHYSIOLOGICAL   CHANGES   IN   TRANSITION. 


283 


TABLE  81. — Respiration-rate  and  pulmonary  ventilation  of  E.  D.  B.  in  periods  of  transition  from  standing 
to  grade  walking.     (Values  per  minute.) — Continued. 


Date,  condition,  and  period  of 
measurement. 

Period  I. 

Period  II. 

Period  HI. 

Period  IV. 

Respi- 
ration- 
rate. 

Pul- 
monary 
venti- 
lation 
(unre- 
duced) . 

Respi- 
ration- 
rate. 

Pul- 
monary 
venti- 
lation 
(unre- 
duced). 

Respi- 
ration- 
rate. 

Pul- 
monary 
venti- 
lation 
(unre- 
duced). 

Respi- 
ration- 
rate. 

Pul- 
monary 
venti- 
lation 
(unre- 
duced). 

March  16,  1916—cont'd. 
Walking,  40  p.  ct.  ;  av.  66.1  meters  —  con. 
Following  1  /4  min.  : 
1st  

26.6 
28.0 
24.6 
27.1 

liters. 
58.3 
67.4 
66.5 
77.5 

21.6 
24.4 
29.6 
29.4 

liters. 
51.0 
61.3 
79.1 
78.0 

25.3 
29.3 
26.6 
27.3 

liters. 
51.0 
70.8 
71.3 
79.6 

23.4 

24.7 
31.4 
29.9 

liters. 
59.8 
69.9 
87.5 
88.6 

2d  

3d  

4th  

5th  

27.5 
27.5 
28.9 
30.4 

76.8 
84.1 
86.3 
88.4 

27.5 
31.0 
31.0 
31.0 

80.0 
90.1 
93.9 
94.5 

31.2 
34.0 
32.9 
36.0 

88.0 
98.9 
98.8 
109.9 

34.1 
31.4 
34.1 
34.1 

99.7 
96.5 
98.4 
98.4 

6th  

7th  

8th  

9th  

30.0 
31.8 
28.6 

88.2 
97.1 
91.1 

29.9 
31.0 
29.9 

96.3 
97.2 
93.7 

32.4 
31.5 
34.7 

16.7 

25.9 
20.8 
25.9 
25.4 
27.7 

97.0 
96.5 
103.4 

12.2 

24.7 
21.2 
26.1 
29.3 
35.1 

36.0 
37.1 
36.5 

106.8 
110.0 
108.4 

10th  

llth  

February  £4,  1916. 
Standing,  av.  of  3  minutes  

Walking,  45  p.  ct.;  av.,  44.8  meters: 
Measured  in  1/5  min.: 
1st  

2d  

3d  

4th  

6th  

6th  

29.3 
29.3 
25.4 
28.9 
31.2 

37.0 
44.8 
44.7 
50.1 
56.5 

7th  

8th  

9th  

10th  

llth  

27.9 
24.1 
28.1 
30.0 
29.0 

50.3 
51.4 
51.9 
58.2 
61.5 

12th  

13th  

14th  

15th  

16th  

26.3 
35.0 
39.2 
33.7 
31.3 

49.5 
73.2 
92.6 
89.4 
81.9 

17th  

18th  

19th  

20th  

21st  

31.3 
33.7 
30.0 

32.0 
34.0 
34.0 
36.5 

85.8 
92.9 
87.1 

90.5 
96.6 
95.1 
101.6 

22d  

23d  ."  

Following  minutes: 
1st  

2d  

3d  

4th  

284 


METABOLISM   DURING   WALKING. 


CHANGES  IN  PULMONARY  VENTILATION. 

The  data  for  the  pulmonary  ventilation  (uncorrected  for  tempera- 
ture changes)  are  also  included  in  table  81,  and  are  measured  from  the 
kymograph  curves  in  the  same  time-lengths  as  the  respiration-rate, 
i.  e.,  full  minutes  for  the  standing  position  and  12  seconds  and  15  sec- 
onds for  the  walking.  When  the  subject  changed  from  standing  to 
walking,  the  measured  values  indicate  that  the  ventilation  doubled 
within  the  first  12  seconds  and  continued  to  increase  throughout  the 
first  and  into  the  second  minute.  By  the  close  of  the  second  minute 
this  increase  appeared  to  diminish  in  several  of  the  periods,  but,  as  a 
rule,  it  continued  into  the  third  minute.  Beyond  the  third  minute, 
though  increases  occasionally  appear  in  the  values,  they  were  not  per- 
sistent, and  are  without  uniformity  in  direction.  The  values  in  the 
fifth  minute  are  seldom  larger  or  even  as  large  as  those  found  in  some 
of  the  earlier  minutes.  While  the  figures  show  wide  variations,  the 
general  picture  which  they  convey  is  that  the  immediate  effect  of  the 
work  upon  the  ventilation  was  compensated  for  by  the  end  of  the 
third,  or  possibly  the  beginning  of  the  fourth  minute,  and  probably  the 
ventilation  reached  approximate  constancy  by  the  time  the  subject 
had  maintained  a  uniform  rate  of  walking  for  4  minutes.  The  ventila- 
tion during  the  periods  on  March  9  had  a  decided  rhythmic  effect 
which  makes  it  uncertain  whether  or  not  on  this  day  the  effect  of  the 
work  on  the  ventilation  was  offset  by  the  third  minute.  This  rhythm, 
however,  is  not  apparent  on  any  of  the  other  days. 

CHANGES  IN  RATE  OF  OXYGEN  CONSUMPTION  (UNREDUCED). 

The  changes  in  the  rate  of  the  oxygen  consumption  (unreduced)  as 
the  subject  passed  from  standing  to  walking  are  shown  in  table  82. 
These  include  data  for  both  standing  and  walking  on  March  9,  14, 
15,  16,  and  17,  1916.  A  few  values  obtained  on  February  24  are  also 
given. 

TABLE  82. — Rate  of  oxygen  consumption  of  E.  D.  B.  in  periods  of  transition  from  standing  to 

grade  walking. 


Date,  condition,  and  period  of  measurement. 

Oxygen  consumption  (unreduced)  per  minute. 

Period  I. 

Period  II. 

Period  III. 

Period  IV. 

March  9,  1916. 
Standing,  measured  in  minutes  

c.  c. 
269 
290 
301 

1,527 

c.  c. 

269 
280 
290 

1,484 

c.  c. 
290 
301 
301 

1,398 

c.  c. 

Walking;  30  p.  ct.;  av.,  49  meters: 
Measured  in  }/%  min.  : 
2d  

301 
301 

1,527 

3d  

1,570 

1,558 
1,667 

1,387 
2,008 

1,527 
1,955 

4th  

PHYSIOLOGICAL   CHANGES   IN   TRANSITION. 


285 


TABLE  82. —  Rate  of  oxygen  consumption  of  E.  D.  B.  in  periods  of  transition  from  standing  to 

grade  walking. — Continued. 


Date,  condition,  and  period  of  measurement. 

Oxygen  consumption  (unreduced)  per  minute. 

Period  I. 

Period  II. 

Period  III. 

Period  IV. 

March  9,  1916  —  cont'd. 
Walking,  30  p.  ct.  ;  av.  49  meters  —  cont'd. 
Measured  in  J^  min.  —  cont'd. 
5th  

c.  c. 
2,000 
1,957 

c.  c. 

1,978 
1,935 

c.  c. 
2,000 
1,978 

c.  c. 
2,021 
2,107 

6th  

7th  

1,828 
2,020 

1,729 
2,494 

2,247 
2,236 

8th  

2,107 

9th  

2,021 
2,043 

2,193 
2,107 

2,064 
2,116 

2,236 
2,261 

10th  

llth  

2,135 
2,215 

2,344 
2,408 

2,301 
2,279 

12th  

2,086 

13th  

2,272 

2,150 

2,174 
2,129 

14th  

March  17,  1916. 
Standing,  measured  in  minutes  

312 
323 
269 
258 

237 
280 
344 
258 
312 

344 
376 
312 
269 

312 

290 
333 
301 
247 

Walking,  30  p.  ct.;  av.,  53  meters: 
Measured  in  J^  min.  : 
1st  

1,139 
1,613 

2d  

1,312 

1,462 

1,247 

3d  

2,021 
2,172 

1,699 
1,871 

1,957 
1,914 

1,892 
2,215 

4th  

5th  

2,233 
2,279 

1,935 
2,287 

1,978 
2,451 

2,282 
2,430 

6th  

7th  

2,344 
2,452 

2,236 
2,279 

2,451 
2,483 

2,473 
2,428 

8th  

9th  

2,387 
2,344 

2,334 
2,430 

2,473 
2,408 

2,277 
2,322 

10th  

llth  

2,335 

2,344 

2,408 

2,322 

March  14,  1916. 
Standing,  measured  in  minutes  

269 

290 
269 
247 
215 

258 
258 
269 
258 

258 
301 
323 
215 

Walking,  30  p.  ct.;  av.,  60  meters: 
Measured  in  J^  min.  : 
1st  

301 
333 
237 
258 

1,288 
1,441 

2d  

2,129 

1,560 

1,140 

3d  

1,957 
2,057 

1,828 
2,322 

1,914 
2,258 

1,806 
2,150 

4th  

5th  

2,561 
2,752 

2,580 
2,462 

2,262 
2,449 

6th  

2,537 

286 


METABOLISM   DURING   WALKING. 


TABLE  82. — Rate  of  oxygen  consumption  of  E.  D.  B.  in  periods  of  transition  from  standing  to 

grade  walking — Continued. 


Date,  condition,  and  period  of  measurement. 

Oxygen  consumption  (unreduced)  per  minute. 

Period  I. 

Period  II. 

Period  III. 

Period  IV. 

March  14,  1916—  cont'd. 
Walking,  30  p.  ct.  ;  av.  60  meters  —  cont'd. 
Measured  in  J^  min.  —  cont'd. 
7th     

c.  c. 

2,724 
2,694 

c.c. 
2,473 
2,469 

c.  c. 

2,408 
2,408 

c.c. 

2,494 
2,551 

8th        

9th  

2,666 

2,494 
2,437 

2,484 
2,365 

2,795 
2,693 

10th  

March  15,  1916. 
Standing,  measured  in  minutes  

312 
301 
323 

290 
280 
258 
312 

312 

280 
258 
258 

1,505 

Walking,  30  p.  ct.;  av.,  70  meters: 
Measured  in  j^  min.  : 
2d  

323 
323 

258 

1,871 

1,548 

3d  

2,043 
2,614 

2,129 
2,150 

2,064 
2,494 

1,914 

2,387 

4th                   

5th  

2,688 
2,774 

2,772 
2,989 

2,855 
2,881 

2,749 
2,752 

6th  

7th  

3,141 
2,989 

2,820 
2,817 

3,023 
3,118 

8th  

3,075 

9th  

3,035 

2,838 

2,881 

3,144 

March  16,  1916. 
Standing,  measured  in  minutes  

333 

355 
355 
344 

312 
290 
366 
258 

Walking,  40  p.  ct.;  av.,  66  meters: 
Measured  in  %  min.  : 
1st  

258 
323 

280 
321 

1,363 
1,656 

2d  

1,697 

1,957 

1,937 

3d  

2,150 
2,634 

2,279 
3,047 

2,043 
2,094 

2,559 
3,395 

4th  

5th  

3,268 
3,326 

3,161 
3,293 

3,698 
3,333 

3,440 
3,505 

6th  

7th  

3,354 

3,311* 

3,419 
3,611 

3,483 

8th  

February  £4,  1916. 
Standing,  av.  of  3  minutes  

287 

556 
560 
649 
874 
835 

Walking,  45  p.  ct.;  45  meters: 
Measured  in  1/5  min.  : 
1st  

2d  

3d  

4th  

5th  

6th  

1,207 
1,364 
1,530 

7th  

8th  

PHYSIOLOGICAL   CHANGES   IN   TRANSITION.  287 

The  values  for  the  oxygen  consumption  during  standing  are  measured 
in  minutes  from  the  kymograph  record  during  3  or  more  of  the  5  or  6 
minutes  preceding  the  tune  of  transition  to  walking.  These  unre- 
duced values  for  the  oxygen  consumption  range  somewhat  about  an 
average  of  300  c.  c.  per  minute.  On  March  16,  especially  in  the 
first,  second,  and  fourth  periods,  the  respiration  was  uneven  and  the 
measurement  of  the  kymograph  curve  was  difficult. 

During  the  first  30  seconds  of  walking,  the  tracings  were  usually  too 
irregular  to  determine  the  rate  of  oxygen  consumption,  but  in  the  second 
half -minute  we  find  the  oxygen  consumption  was  in  almost  every  in- 
stance over  1,400  c.  c.,  or  from  four  to  five  times  the  standing  require- 
ment. As  a  rule,  in  the  third  half-minute  the  oxygen  consumption 
increased  an  additional  300  to  500  c.  c.,  or  a  further  increase  of  about 
one-quarter  of  that  which  occurred  in  the  second  half-minute.  The 
values  for  the  fourth  half-minute  are  approximately  of  the  same  charac- 
ter as  those  hi  the  third  half-minute,  but  with  the  increases  over  the 
preceding  half-minute  somewhat  diminished.  By  the  fifth  half-min- 
ute, and  certainly  by  the  sixth  half-minute  (from  2\  to  3  minutes  after 
the  walking  began),  the  oxygen  consumption  apparently  reached  a 
point  indicating  that  the  rate  of  consumption  was  commensurate  with 
the  body  requirements  for  the  work  in  hand.  Beyond  this  point  the 
rate  of  oxygen  consumption  remained  essentially  uniform  for  the  re- 
mainder of  the  experimental  period,  irrespective  of  the  amount  of 
work  being  performed. 

REBPIKATORY  CHANGES  IN  TRANSITION  FROM  GRADE  WALKING  TO  STANDING. 

The  respiratory  changes  during  the  transition  from  grade  walking 
to  standing  were  also  measured  in  like  manner  as  those  for  the  transi- 
tion from  standing  to  grade  walking.  (See  fig.  38,  p.  278.)  The  values 
for  the  respiration-rate  and  pulmonary  ventilation  are  given  in  tables 

83  and  84  and  for  the  rate  of  oxygen  consumption  in  table  85. 

In  eight  of  these  experiments  the  transition  was  measured  during  the 
final  standing  period  after  the  subject  had  been  walking  during  the 
preceding  periods  of  the  forenoon.  The  walking  stopped  simulta- 
neously with  the  beginning  of  the  period  and  the  respiration-rate 
and  pulmonary  ventilation  were  measured  and  compared  with  the 
average  values  for  the  preceding  walking  periods.  (See  table  83.) 
On  only  three  of  these  days  was  an  attempt  made  to  estimate  the  oxy- 
gen consumption,  and  then  only  with  the  subject  standing. 

On  March  10  and  11,  in  addition  to  the  preliminary  walking,  the 
subject  walked  3  or  4  minutes  of  the  period  and  then  stood.  Observa- 
tions for  four  periods  were  obtained  on  these  two  days.  During  these 
periods,  the  respiration,  ventilation,  and  oxygen  consumption  were 
determined  for  both  the  walking  and  standing  portions.  (See  tables 

84  and  85.)    The  subject  rested  in  the  intervals  between  periods  and 


288 


METABOLISM   DURING   WALKING. 


then  had  a  preliminary  walk  in  order  to  make  the  conditions  as 
nearly  alike  as  possible. 


CHANGES  IN   RESPIRATION-RATE. 


The  respiration-rates  during  the  walking  periods  show  variations  in 
the  measurements  per  minute,  but,  on  the  whole,  indicate  what  may  be 
accepted  as  the  average  for  walking  in  each  period.  A  comparison 
of  these  rates  with  those  obtained  immediately  after  walking  ceased 
shows  that  the  respiration-rate  falls  during  the  first  12  seconds  of  stand- 
ing in  all  but  three  instances,  i.  e.,  February  14  and  15,  and  the  second 
period  of  March  10.  The  decline  is  small  in  some  cases,  and  none  of 
the  decreases  exceed  the  rate  of  6.5  respirations  per  minute,  while  the 
rate  for  the  majority  is  less  than  4  respirations  per  minute.  In  the  suc- 
ceeding fractions  of  the  first  minute  the  records  show  increases  and 
decreases  without  uniformity,  although  by  the  end  of  the  minute  the 
rates  may  possibly  be  said  to  be  lower  on  the  whole  than  at  the  begin- 
ning of  the  standing.  The  notable  fact  is  that  the  change  in  respira- 
tion-rate is  slight  in  the  transition  from  walking  to  standing.  Further- 
more, if  16  respirations  per  minute  be  taken  as  the  normal  respiration- 
rate  for  E.  D.  B.  in  the  standing  position,  we  find  that  in  one  or  two 
instances  this  value  is  approached  during  the  second  or  third  minute 
after  walking  ceased,  but  the  rate  is  not  maintained.  In  nearly  every 
case  the  rate  is  above  the  normal  standing  value  during  the  fifth  min- 
ute, while  most  of  those  records  which  extend  into  the  seventh  and 
eighth  minutes  show  that  the  respiration-rate  is  still  above  the  normal. 
This  course  is  in  contrast  to  the  behavior  of  the  respiration-rate  in  the 
transition  from  standing  to  walking,  for  the  response  under  those  con- 
ditions was  largely  within  the  first  12  seconds  and  a  uniform  rate  had 
been  attained  by  the  end  of  the  first  minute  of  .walking. 

TABLE  83. — Respiration-rate  and  pulmonary  ventilation  of  E.  D.  B.  in  periods  of  transition 
from  grade  walking  to  standing.     (Values  per  minute.) 


Date,  condition,  and  period 
of  measurement. 

Respi- 
ration- 
rate. 

Pul- 
monary 
venti- 
lation 
(unre- 
duced). 

Date,  condition,  and  period 
of  measurement. 

Respi- 
ration- 
rate. 

Pul- 
monary 
venti- 
lation 
(unre- 
duced). 

January  1,  1916. 
Walking,    20   p.    ct.;   81.6 
meters: 
Meas.  in  minutes  

31.0 

liters. 
53.0 

January  1,  1916  —  cont'd. 
Standing  —  cont'd. 
Meas.  in  1  /5  min.  —  cont'd 

litert. 

30  6 

51  7 

6th  

25.0 

30.4 

Last  full  minute  

27  6 

54  2 

7th  

24.0 

24.1 

Standing: 

8th  

22.9 

22.8 

Meas.  in  1/5  min.  : 

9th  

18.5 

18.3 

1st  

26  5 

49  3 

10th  

22.2 

19.0 

2d 

21    9 

«>c  n 

3d  

26  5 

35  1 

llth  

19.2 

22.1 

4th  

26  5 

35  4 

12th  

20.0 

13.3 

5th  

21  8 

25  6 

13th  

21.8 

12.8 

PHYSIOLOGICAL   CHANGES   IN   TRANSITION. 


289 


TABLE  83. — Respiration-rate  and  pulmonary  ventilation  of  E.  D.  B.  in  periods  of  transition 
from  grade  walking  to  standing.     (Values  per  minute.) — Continued. 


Date,  condition,  and  period 
of  measurement. 

Respi- 
ration- 
rate. 

Pul- 
monary 
venti- 
lation 
(unre- 
duced). 

Date,  condition,  and  period 
of  measurement. 

Respi- 
ration 
rate. 

Pul- 
monary 
venti- 
lation 
(unre- 
duced). 

January  1,  1916  —  cont'd. 
Standing  —  cont'd. 
Meas.  in  1/5  min.  —  cont'd. 
14th    

22  2 

liters, 
12  2 

January  S,  1916  —  cont'd. 
Standing  —  cont'd. 
Following  J^  min.  —  cont'd. 
5th  

20  0 

liters. 
12  9 

15th 

20  3 

11   1 

6th  

19  0 

12.2 

16th  

17  0 

9.9 

February  12,  1916. 

17th  

14  7 

10  4 

Walking,    30    p.    ct.;    74.6 

18th    

11  0 

5  2 

meters  : 

19th    

18  2 

8  9 

Meas.  in  min  

31.6 

71.8 

Following  1/2  min.  : 
1st  

19.9 

10.1 

27.6 
29.2 

67.3 
70.8 

2d  

20  7 

10.8 

29.2 

70.4 

28  7 

71  0 

3d 

21  7 

9  7 

Last  full  minute  

28.8 

71.4 

4th  

19  9 

10.9 

Standing: 

5th 

19  3 

10  8 

1st  

26.7 

67.9 

6th 

18  9 

9  6 

2d  

26  7 

65.8 

3d 

28  1 

55  0 

January  S   1916 

4th  

31  4 

43.6 

Walking     25    p.    ct.  ;    42.3 

5th  

26.7 

37.0 

Meas  in  minutes 

24  0 

30  1 

6th  

22.3 

34.6 

24  6 

1  31  2 

7th  

26.7 

28.5 

23  2 

32  6 

8th  

28.1 

29.9 

9th  

26.2 

30.6 

Meas.  in  1/5  min.  : 

10th  

23.4 

27.2 

lof 

99    ^ 

Qfl    4. 

2d               

20  9 

25  1 

llth  

22.3 

23.7 

3d 

17  1 

20  2 

12th  

19.3 

19.2 

4th 

20  0 

21  1 

13th  

20.5 

17.3 

5th  

25  7 

21  0 

14th  

16.6 

11.7 

15th 

18  6 

10  9 

RtVi 

91    8 

91    8 

7th 

19  2 

16  8 

16th  

19.3 

12.7 

8th 

21  8 

16  2 

17th  

21.9 

15.4 

9th 

20  0 

14  2 

18th  

22.1 

15.4 

10th 

20  9 

15  5 

19th  

21.9 

16.3 

20th 

21  9 

15  8 

llth 

on  q 

14  5 

12th  

20  0 

15  0 

21st  

21.1 

18.3 

13th  

19  2 

13.4 

Following  1/2  min.  : 

14th        

15  8 

12  5 

1st  

24.2 

17.5 

15th        .        ... 

19  4 

14  0 

2d  

19.8 

17.4 

16th            .        .    . 

19  4 

12  0 

3d  

24.4 

15.8 

17th 

21  0 

12  8 

4th  

21.0 

14.2 

IRtVi 

90   9 

Hi 

Following  1/2  min: 

5th  

22.4 

16.4 

1st 

21  3 

13  5 

6th  

20.7 

15.2 

2H 

20  0 

12  8 

7th 

20  0 

14  1 

3d 

20  4 

13  5 

8th  

19.7 

15.3 

4th  

18.4 

12.3 

290 


METABOLISM   DURING   WALKING. 


TABLE  83. — Respiration-rate  and  pulmonary  ventilation  of  E.  D.  B.  in  periods  of  transition 
from  grade  walking  to  standing.     (Values  per  minute.) — Continued. 


Date,  condition,  and  period 
of  measurement. 

Respi- 
ration- 
rate. 

Pul- 
monary 
venti- 
lation 
(unre- 
duced) . 

Date,  condition,  and  period 
of  measurement. 

• 

Respi- 
ration- 
rate. 

Pul- 
monary 
venti- 
lation 
(unre- 
duced). 

February  14,  1918. 
Walking,    30   p.    ct.;   68.8 
meters; 
Meas.  in  minutes  

29.7 

liters. 
61.8 

February  15,  1916  —  cont'd. 
Standing  —  cont'd. 
Meas.  in  1  /5  min.  —  cont'd. 
2d  

34.1 

liters. 
45.5 

27.6 

63.4 

3d  

29.2 

41.8 

32.2 

68.3 

4th  

29.2 

28.7 

25.9 

61.3 

5th  

22.0 

37  1 

94   1 

CO    A 

Standing: 

6th  

26.4 

31.2 

Meas.  in  1/5  min.  : 

7th  

30.0 

23.2 

1st  

30.7 

75.2 

8th  

22.9 

24.8 

2d  

29.6 

63.7 

9th  

22.0 

22.2 

3d  

29.6 

56.2 

10th  

22.5 

21.6 

4th 

30  7 

43  7 

6th  

31.8 

35.1 

llth  

21.9 

16.1 

12th 

17  7 

11  5 

(5th  

29.6 

37.6 

13th  

16.9 

10.5 

7th  

26.5 

35.0 

14th  

18.9 

12.3 

8th  

26.7 

32.8 

15th  

15.4 

8.4 

Oth 

26  5 

26  5 

10th  

27.6 

21.5 

16th  

21.2 

15.8 

17th 

20  5 

19  0 

llth  

21.6 

12.6 

18th  

23.4 

14.8 

12th  

19.7 

12.8 

19th  

18.9 

12.8 

13th  

21.2 

18.9 

20th  

20.7 

14.1 

14th 

23  8 

17  3 

15th  

25  6 

12  6 

21st  

20  7 

12.8 

22d 

20  d 

15  5 

16th  

25.9 

14.1 

23d  

16.0 

15.4 

17th  

24.6 

17  2 

24th  

19.1 

16.2 

18th  

24  0 

15  8 

25th  

20.7 

10.8 

19th 

24  6 

19  3 

20th  

22.2 

17.2 

26th  

24.0 

15.3 

27th 

22  9 

13  8 

2lst  

22  3 

16.2 

28th  

24.0 

14.5 

22d  

18  4 

12  7 

29th  

24.0 

21.2 

23d  

21.0 

13.7 

Following  1/2  min.: 

24th  .  .  . 

20  3 

11  6 

1st  

20.6 

15.3 

Following  1/2  min  • 

2d  

19.1 

12.5 

1st 

19  3 

15  3 

2d  

19.5 

13.2 

3d  

21.6 

14.6 

4th 

20  8 

14  4 

3d 

20  7 

13  8 

4th  

20.5 

14.1 

February  16,  1916. 

Wnltinir       *\z>      n       r>t    •      ^ft  ft 

5th  

20.8 

14.7 

meters; 

6th  

19.6 

13.9 

Meas.  in  minutes  

30.4 

59.9 

98   9 

RQ    A 

February  IB,  1916. 

Last  full  minute  

28.8 

59.2 

Walking,    35   p.    ct.;   46.2 
meters  : 
Meas.  in  minutes 

31.3 

46  9 

Standing: 
Meas.  in  1/5  min.  : 
1st  

28.4 

51.4 

29.8 

46  9 

2d  

30.7 

48.9 

Last  full  minute 

29.2 

47  0 

3d  

27.1 

43.5 

Standing: 

4th  

26.4 

35.4 

Meas.  in  1/5  min.  : 

5th  

25.4 

34.6 

1st  

34.1 

54.2 

PHYSIOLOGICAL   CHANGES   IN   TRANSITION. 


291 


TABLE  83. — Respiration-rate  and  pulmonary  ventilation  of  E.  D.  B.  in  periods  of  transition 
from  grade  walking  to  standing.     (Values  per  minute.} — Continued. 


Date,  condition,  and  period 
of  measurement. 

Respi- 
ration- 
rate. 

Pul- 
monary 
venti- 
lation 
(unre- 
duced). 

Date,  condition,  and  period 
of  measurement. 

Respi- 
ration- 
rate. 

Pul- 
monary 
venti- 
lation 
(unre- 
duced) . 

February  16,  1916  —  cont'd. 
Standing  —  cont'd. 
Meaa.  in  1  /5  min.  —  cont'd. 
6th  

25.4 
25.4 
27.6 
24.0 
24.0 

liters. 
30.6 
19.5 
21.3 
24.1 
22.0 

February  17,  1916  —  cont'd. 
Standing  —  cont'd. 
Meas.  in  1  /5  min.  —  cont'd. 
13th  

23.2 
23.2 
23.2 

liters. 
17.8 
17.3 
16.0 

7th  

14th. 

8th  

15th 

9th 

16th 

10th  

23.3 
21.6 
22.0 
22.0 
19.4 

18.1 
15.9 
16.1 
19.3 
15.7 

llth  

17th 

20.8 
19.2 
18.4 
18.4 
17.7 

21.4 
15.9 
18.9 
17.9 
13.9 

18th 

12th  

19th 

13th  

20th  

14th 

Following  1/2  min.: 
1st 

15th  

22.1 
21.8 

16.6 
16.5 

16th  

13.3 
16.9 
20.8 
22.7 
20.0 

9.4 
13.4 
14.8 
14.5 
14.0 

2d     

17th 

3d     

18th  

19.9 
20.4 

16.0 
13.5 

19th  

4th       

20th 

Following  minutes  : 
1st  

Following  1/2  min.: 
1st  

20.0 
20.4 

14.8 
15.1 

21.6 
21.3 

16.3 
14.2 

2d  

2d 

February  25,  1916. 
Walking,    30    p.    ct.;    59.6 
meters: 
Last  full  minute  

3d  

32.0 

25.5 
22.1 
22.2 
20.9 
17.8 

50.3 

44.0 
33.5 
27.9 
21.4 
19.4 

19.4 
19.5 

14.6 
13.5 

4th  

5th  

20.5 
22.7 

13.2 
15.7 

6th  

Standing: 
Meas.  in  1/5  min.: 
1st  

February  17,  1916. 
Walking,    35    p.    ct.;    62.5 
meters  : 
Meas.  in  minutes  

30.0 
27.2 
28.5 
29.3 
29.0 

24.8 
29.7 
30.3 
29.7 
23.6 

69.5 
67.1 
69.8 
71.8 
71.2 

57.0 
52.1 
44.1 
46.4 
42.7 

2d  

3d  

4th      

Last  full  minute  

5th  

6th  

17.1 
21.0 
22.0 
14.7 
13.2 

16.0 
17.8 
13.5 
10.3 
9.9 

7th  

Standing  : 
Meas.  in  1/5  min.  : 
1st  

8th  

9th  

10th 

2d 

llth  

3d  

17.2 
20.5 
18.8 
20.2 
13.3 

13.2 
11.9 
14.5 
10.3 
7.1 

4th  

12th  

5th  

13th   

6th  

14th 

28.4 
22.6 
21.7 
19.8 
21.7 

25.3 
27.6 
20.8 
18.4 
19.9 

15th    . 

7th 

16th  

8th  

14.6 
13.8 

15.9 
19.5 

9.2 
9.2 

9.1 
8.9 

9th  

17th           .        .    . 

10th  

Following  1/2  min.: 
1st 

llth  

23.2 
21.1 

19.0 
18.5 

12th  

2d  

292 


METABOLISM   DURING   WALKING. 


TABLE  83. — Respiration-rate  and  pulmonary  ventilation  of  E.  D.  B.  in  periods  of  transition 
from  grade  walking  to  standing.     (Values  per  minute.) — Continued. 


Date,  condition,  and  period 
of  measurement. 

Respi- 
ration- 
rate. 

Pul- 
monary 
venti- 
lation 
(unre- 
duced). 

Date,  condition,  and  period 
of  measurement. 

Respi- 
ration- 
rate. 

Pul- 
monary 
venti- 
lation 
(unre- 
duced) . 

February  £5,  1916  —  cont'd. 
Standing  —  cont'd 
Following    1  /2   min.  — 
cont'd. 
3d  

18.0 

liters. 
9.4 

February  86,  1916  —  cont'd. 
Standing  —  cont  'd. 
Following    1  /2    min.  — 
cont'd. 
9th  

liters. 

4th  

17.3 

9.9 

10th  

12  8 

8  4 

5th  

16  8 

8.6 

llth  

12  9 

9  1 

6th  

15.4 

9.3 

12th  

14.4 

9.9 

7th  

16  0 

8  0 

13th  

13  6 

9  9 

8th  

17.3 

9.4 

TABLE  84. — Respiration-rate  and  pulmonary  ventilation  of  E.  D.  B.  in  successive  periods  of  transition  from 
grade-walking  to  standing     (Values  per  minute.) 


Date,  condition,  and  period  of 
measurement. 

Period  I. 

Period  II. 

Period  III. 

Period  IV. 

Respi- 
ration- 
rate. 

Pul- 
monary 
venti- 
lation 
(unre- 
duced). 

Respi- 
ration- 
rate. 

Pul- 
monary 
venti- 
lation 
(unre- 
duced). 

Respi- 
ration- 
rate. 

Pul- 
monary 
venti- 
lation 
(unre- 
duced). 

Respi- 
ration- 
rate. 

Pul- 
monary 
venti- 
lation 
(unre- 
duced). 

March  10,  1916, 
Walking,  30  p.  ct.;  av.,  53.3  meters: 
Measured  in  minutes  

26.4 
30.4 
30.8 
30.4 
33.3 

27.1 

26.8 
31.7 
24.8 
22.0 

liters. 
56.5 
73.1 
68.6 
71.2 
74.7 

52.2 
44.7 
40.2 
27.4 
23.9 

liters. 

liters. 

liters. 

Last  full  minute  

28.7 
30.3 
28.0 
30.5 

32.1 
30.8 
29.5 

28.7 
28.7 

60.7 
76.0 
61.7 
72.4 

74.2 
64.0 
51.7 
46.3 
36.9 

30.0 
29.7 
32.3 
32.3 

28.5 
24.1 
22.4 
23.2 
31.2 

61.7 
75.5 
76.6 
76.1 

54.8 
39.1 
28.5 
22.5 
27.7 

30.8 
30.2 
33.3 
32.4 

28.1 
24.6 
23.6 
24.6 
22.7 

60.3 
72.6 
66.4 
72.9 

52.3 
44.0 
39.8 
33.4 
24.7 

Standing,  measured  in  1/5  min.  : 
1st  

2d  

3d  

4th  

5th  

6th  

21.4 
19.3 
21.2 
18.7 
22.4 

20.3 
18.7 
19.0 
17.1 
19.1 

17.9 
23.3 
18.5 
17.4 
19.2 

16.3 
19.9 
15.7 
13.4 
13.4 

32.0 
24.2 
22.3 
21.1 
23.2 

30.1 
28.0 
21.7 
15.8 
18.8 

25.8 
23.0 
23.5 
23.9 
26.7 

20.9 
19.7 
17.7 
19.0 

18.4 

7th  

8th  

9th  

10th  

Following  1/2  min.: 
1st  

20.2 
18.4 

18.2 
17.0 

21.2 
21.6 

16.4 
17.3 

23.6 
22.8 

18.0 
18.0 

20.9 
22.0 

19.1 
17.4 

2d  

3d  

19.7 
17.7 

18.0 
18.4 

23.6 
20.5 

18.5 
19.2 

21.6 
21.7 

17.8 
18.4 

23.7 
21.7 

18.9 
18.2 

4th  

PHYSIOLOGICAL   CHANGES   IN  TRANSITION. 


293 


PABLE  84. — Respiration-^rate  and  pulmonary  ventilation  of  E.  D.  B.  in  successive  periods  of  transition  from 
grade  walking  to  standing.     (Values  per  minute.) — Continued. 


Date,  condition,  and  period  of 
measurement. 

Period  I. 

Period  II. 

Period  III. 

Period  IV. 

Respi- 
ration- 
'  rate. 

Pul- 
monary 
venti- 
lation 
(unre- 
duced). 

Respi- 
ration- 
rate. 

Pul- 
monary 
venti- 
lation 
(unre- 
duced). 

Respi- 
ration- 
rate. 

Pul- 
monary 
venti- 
lation 
(unre- 
duced). 

Reapi- 
ration- 
rate. 

Pul- 
monary 
venti- 
lation 
(unre- 
duced). 

March  10,  1916—  cont'd. 
Standing  —  cont'd. 
Following  1/2  min.  —  cont'd. 
5th  

18.2 
16.7 

liters. 
18.5 
18.2 

19.2 
21.6 

liters. 
17.9 
18.6 

20.0 
21.6 

liters. 
18.0 

18.4 

21.1 
18.2 

liters. 
19.1 
15.0 

6th  

7th  

19.8 
17.3 

20.1 
14.3 

20.2 

17.8 

8th  

March  11,  1916. 
Walking,  30  p.  ct.;  av.,  62.6  meters: 
Measured  in  minutes  

27.0 
28.0 
27.2 
29.7 

25.0 
22.7 
26.8 
27.2 
25.2 

52.2 
63.4 
63.2 
61.7 

47.1 
44.8 
27.8 
24.3 
25.8 

31.0 
32.0 
32.5 
31.6 

25.7 
27.0 
26.7 
28.8 
22.2 

56.2 
71.2 
67.7 
63.8 

42.8 
34.3 
27.7 
27.4 
22.2 

31.3 
31.9 
32.2 
30.8 

24.3 
22.7 
21.8 
19.9 
19.9 

59.0 
72.2 
64.5 
68.6 

46.3 
34.0 
26.8 
23.3 

18.5 

30.2 
31.4 
29.5 
32.0 

27.1 
23.4 
23.4 
24.4 
20.3 

56.9 
67.6 
67.1 
62.8 

50.6 
41.0 
31.1 
28.9 
21.2 

Last  full  minute  

Standing,  measured  in  1/5  min.  : 
1st  

2d  

3d  

4th  

5th  

6th  

22.8 
21.1 
18.2 
18.9 
18.8 

20.9 
17.3 
14.7 
15.7 
15.7 

22.5 
23.2 
22.2 
20.4 
20.3 

19.1 
20.1 
18.9 
17.7 
17.0 

18.5 
24.8 
33.5 
23.1 
19.1 

15.3 
23.0 
22.2 
21.2 
14.3 

20.0 
16.8 
27.3 
19.7 
20.6 

23.0 
13.3 
14.6 
20.2 
16.4 

7th  

8th  

9th  

10th  

Following  J^  min.  : 
let  

19.4 
20.8 

14.3 
16.6 

20.3 
20.4 

17.1 

16.8 

21.3 
19.6 

16.6 
16.4 

20.2 
20.2 

13.9 
15.9 

2d  

3d  

18.9 
20.6 

14.8 
15.6 

20.4 
17.3 

17.7 
15.0 

19.0 
19.4 

14.9 
15.3 

21.1 
21.8 

15.3 
16.1 

4th  

6th  

20.1 
18.5 

15.4 
13.8 

20.1 
18.7 

16.6 
16.0 

20.9 
21.3 

16.1 
16.4 

20.9 
22.0 

15.8 
17.0 

6th  

7th  

18.0 
17.2 

14.4 
14.6 

19.7 

16.3 

21.8 

18.0 

20.3 

14.6 

8th 

CHANGES  IN  PULMONARY  VENTILATION. 

The  response  to  the  lessened  demands  of  the  body  indicated  by 
changes  in  the  pulmonary  ventilation  on  the  cessation  of  walking  is 
very  noticeable  and  different  in  this  respect  from  the  results  found  for 
the  respiration-rate.  In  the  first  12  seconds  of  standing,  the  pulmo- 
nary ventilation  fell  in  all  but  three  instances  and  in  amounts  from  1 
to  23  liters.  This  decrease  continued  throughout  the  first  and  second 
minutes,  and  usually  longer.  By  the  end  of  the  first  minute  the  fall 


294 


METABOLISM   DURING   WALKING. 


TABLE  85. — Rate  of  oxygen  consumption  of  E.  D.  B.  in  periods  of  transition  from  grade  walking 

to  standing. 


Date,  condition,  and  period  of  measurement 
from  transition. 

Oxygen  consumption  (unreduced)  per  minute. 

Period  I. 

Period  II. 

Period  III 

Period  IV. 

January  1,  1916, 
Standing,  measured  in  1/5  min.: 
2d     

c.c. 

c.  c. 

c.  c. 

c.c. 

2.1501 
1,720! 
1,82s1 
1,505! 

2,596 
2,649 
1,429 

2,662 
1,630 
1,278 

3d         

4th        

5th  

February  14,  1916. 
Standing,  measured  in  1/5  min.  : 
2d  

3d  

4th  

February  17,  1916. 
Standing,  measured  in  1/5  min.: 
2d  

3d  

4th  

March  10,  1916. 
Walking,  30  p.  ct.;  av.,  63.3  meters: 
Measured  in  minutes: 
5th  

1,870 
1,862 
2,279 
2,220 
2,226 

4th  

1,861 
2,162 
2,625 
2,182 

1,909 
2,005 
2,243 
2,599 

1,935 
1,670 
2,118 
2,658 

3d  

2d  

1st  

Standing,  measured  in  1/5  min.: 
1st  

2,580 
2,473 
1,935 
1,505 
1,129 

2,311 
2,258 
,2,311 

2,795 
2,795 
2,150 
1,075 

2,473 
2,096 
2,043 
1,881 
1,451 

2d  

3d  

4th  

5th  

1,398 

6th  

860 
753 
484 
484 
376 

1,236 

753 
753 
699 
538 
591 

1,129 
914 
645 

7th  

8th  

645 
538 
484 

9th  

10th  

430 

Following  1/2  min.: 
1st  

366 
430 

452 
344 

516 
430 

452 
409 

2d  

3d  

387 
366 

344 

387 

409 
344 

409 
452 

4th  

5th  

280 

452 
409 

387 
344 

6th  

445 

7th  

421 

1,910 
1,984 
2,354 
2,779 

344 

2,023 
1,971 
2,290 
2,324 

March  11,  1916. 
Walking,  30  p.  ct.;  av.,  52.6  meters: 
Measured  in  minutes: 
4th  

1,838 
1,884 
2,022 
2,169 

2,199 
1,949 
2,172 
2,389 

3d  

2d  

1st  

'Period  V. 


PHYSIOLOGICAL    CHANGES   IN   TRANSITION. 


295 


TABLE  85. — Rate  of  oxygen  consumption  of  E.  D.  B.  in  periods  of  transition  from  grade  walking 

to  standing — Continued. 


Date,  condition,  and  period  of  measurement 
from  transition. 

Oxygen  consumption  (unreduced)  per  minute. 

Period  I. 

Period  II. 

Period  III. 

Period  IV. 

March  11,  1916  —  cont'd. 
Standing,  measured  in  1/5  min.: 
1st  

c.  c. 
2,365 
2,365 

c.  c. 
2,311 
1,989 

c.  c. 
3,064 
2,688 
1,720 
1,236 
1,075 

c.  c. 
2,473 
2,903 

1,881 
1,236 
968 

2d  

3d  

4th  

6th  

1,021 

914 

6th  

806 
645 

538 
484 
484 

860 
645 
645 
484 
430 

968 

645 
699 
591 
591 
645 

7th  

8th  

9th  

484 
538 

10th  

Following  1/2  min.  : 
1st  

387 
366 

452 

387 

473 

452 

538 
473 

2d  

3d  

366 
323 

387 
366 

409 
430 

452 
387 

4th  

5th  

344 

344 

366 
366 

387 
344 

387 
409 

6th  

7th  

301 
301 

266 

445 

8th  

had  amounted  to  40  to  60  per  cent  of  the  ventilation  during  walk- 
ing. If  the  normal  ventilation  of  E.  D.  B.  for  the  standing  position 
be  taken  as  11  liters  per  minute  (unreduced),  as  would  appear  to  be 
the  case  from  the  values  in  table  81,  it  is  seen  that  this  value  was 
approached  in  a  number  of  instances  in  the  third  minute  after  walk- 
ing ceased.  These  values  are  not  maintained  in  most  of  the  cases, 
but  are  succeeded  by  a  higher  ventilation,  from  which  it  begins  slowly 
to  fall.  In  most  of  the  records,  however,  the  ventilation  appears  to 
be  in  the  region  of  15  liters  per  minute  and  to  be  still  above  the  nor- 
mal standing  value  after  5  minutes  of  standing.  On  but  three  days 
(January  1  and  3,  and  February  25)  does  the  ventilation  appear  to  be 
adjusted  to  the  pre- walking  value  before  the  end  of  the  measurements. 
This  would  indicate  that  the  body  was  striving  to  eliminate  the  large 
excess  of  carbon  dioxide  previously  formed  in  the  work  of  walking. 

CHANGES   IN  RATE  OP  OXYGEN   CONSUMPTION    (UNREDUCED). 

Comparison  measurements  of  the  unreduced  oxygen  consumption 
during  standing  and  walking  experiments  were  made  from  the  kymo- 
graph records  on  March  10  and  11,  1916,  only.  These  measurements, 
which,  immediately  after  the  transition,  were  made  in  one-fifth  min- 
utes, are  recorded  in  table  85.  A  few  measurements  of  the  oxygen  con- 


296  METABOLISM   DURING   WALKING. 

sumption  during  standing  were  also  made  on  January  1,  February  14 
and  17,  1916.  These  results  are  likewise  included  in  table  85,  and 
show  that  during  the  first  minute  of  standing  after  walking  ceased  there 
was  a  contraction  in  the  oxygen  consumption  ranging  from  600  to 
1,400  c.  c.  between  the  second  and  the  fourth  or  fifth  fractions  of  the 
first  minute.  No  measurements  were  made  for  the  first  one-fifth  min- 
ute of  standing  on  account  of  irregularities  in  the  record,  and  no 
measurements  of  the  oxygen  consumption  during  walking  on  these 
dates  are  available  for  the  transition  period.  Any  real  comparison 
must  therefore  be  confined  to  the  two  days  for  which  we  have  more 
nearly  complete  data. 

The  results  for  March  10  and  11,  1916,  include  both  walking  and 
standing  values  for  four  periods  on  each  d#y.  The  first  point  which 
attracts  attention  is  the  fact  that  the  oxygen  consumption  during  the 
first  two  one-fifth  minute  measurements  for  standing  usually  indicates 
an  increase  over  the  walking  rate.  The  tracings  in  this  portion  of  the 
transition  record  were  always  irregular  at  their  low  points,  implying 
that  the  transition  disturbed  the  normal  type  of  respiration.  It  is  thus 
difficult  to  determine  the  course  of  the  rise  in  these  few  seconds,  since 
an  error  of  2  mm.  represents  approximately  80  c.  c.,  and  a  few  disturbed 
respirations  at  this  point  could  easily  introduce  an  error  of  double  this 
amount  hi  the  probable  course.  This  disturbance  presumably  rep- 
resented a  temporary  alteration  hi  the  residual  air  in  the  lungs.  It  is 
only  after  these  first  disturbances  have  passed  that  the  true  change 
taking  place  in  the  oxygen  consumption  is  apparent.  This  point  was 
reached  by  the  third  or  fourth  one-fifth  minute,  when  the  fall  amounted 
to  approximately  400  or  500  c.  c.  By  the  end  of  the  first  minute  the 
oxygen  consumption  had  fallen  to  approximately  one-half  of  the  values 
found  with  the  subject  walking.  The  drop  from  this  point  is  almost 
uniformly  progressive  during  the  second  minute  and  continues  with 
somewhat  less  regularity  to  the  end  of  the  measurement.  If,  from  the 
data  in  table  82,  the  normal  unreduced  oxygen  consumption  of  E.  D.  B. 
for  the  standing  position  be  taken  as  280  c.  c.  per  minute,  it  is  seen 
that  in  only  two  cases  is  there  an  approach  to  this  figure  by  the  end  of 
the  measurement  (see  March  10,  period  1,  and  March  11,  period  3); 
that  is,  during  the  time  that  these  measurements  were  extended  (5  or 
6  minutes),  the  oxygen  consumption  continued  above  the  normal  stand- 
ing requirements.  It  is  also  seen  that,  after  the  first  unreliable  readings 
due  to  a  disturbed  record,  the  fall  was  approximately  uniform. 

CONCLUSIONS  REGARDING  RESPIRATORY  CHANGES  IN  TRANSITION  FROM  GRADE  WALKING 
TO  STANDING  AND  THE  REVERSE. 

From  these  measurements  it  is  thus  found  that  during  the  period  of 
transition  from  standing  to  walking,  the  respiration-rate  responded 
within  12  seconds  and  the  maximum  change  was  over  by  the  end  of  the 
first  minute;  that  the  pulmonary  ventilation  responded  within  the 
first  12  seconds  to  double  the  standing  value,  and  continued  increasing 
through  the  third  minute,  while  the  oxygen  consumption  increased 


PHYSIOLOGICAL   CHANGES   IN   TRANSITION.  297 

4  to  5  times  within  the  first  minute  and  the  increase  was  practically 
over  within  3  minutes.  Under  reverse  conditions,  i.  e.,  in  the  transi- 
tion from  walking  to  standing,  the  respiration-rate  fell  slowly  and 
irregularly  and  was  not  settled  nor  at  its  normal  value  within  8  minutes. 
The  ventilation-rate  fell  promptly  and  within  1  minute  was  one-half  of 
the  value  found  with  the  subject  walking,  this  decrease  continuing,  but 
with  diminishing  force;  after  8  minutes  of  standing  it  was  still  above 
the  normal.  The  oxygen  consumption  was  in  harmony  with  the  pul- 
monary ventilation,  failing  continuously  but  not  reaching  a  pre- 
walking  normal  value  during  the  6  minutes  of  measurement. 

PULSE-RATE  IN  TRANSITION  FROM  STANDING  TO  GRADE  WALKING. 

In  the  comparison  of  the  pulse-rate  for  the  standing  position  with 
that  in  grade  walking  (see  p.  262),  it  was  seen  that  the  rate  in  the  walk- 
ing periods  increased  largely,  the  size  of  the  increases  depending  upon 
the  amount  of  work  done.  The  results  are  given  graphically  in  figures 
30  to  32,  inclusive,  pages  265  to  267.  The  duration  of  the  preliminary 
walking  before  the  experimental  period  began  varied  somewhat,  but 
was  rarely,  if  ever,  less  than  5  minutes,  and  in  most  cases  more  nearly 
15  minutes.  During  this  preUminary  walking  it  was  assumed  that  the 
metabolism  and  physiological  factors  had  become  adjusted  to  the  new 
demand  and  that  the  body  functions  were  acting  on  a  constant,  though 
higher,  plane.  This  assumption  was  confirmed  by  the  general  picture 
for  the  respiration,  ventilation,  and  oxygen  consumption  previously 
discussed.  (See  pp.  278  to  287.)  The  new  level  in  these  cases  was 
reached  by  or  before  the  fourth  minute  of  exercise,  and  most  of  the 
change  occurred  inside  of  1  minute  after  the  exercise  began. 

To  obtain  some  estimate  of  the  alterations  which  take  place  in  the 
pulse-rate  during  the  time  of  change  from  quiescence  to  grade  walking, 
a  number  of  electro-cardiograms  were  made  for  E.  D.  B.  in  the  period 
extending  from  one-half  minute  before  the  grade  walking  began  through 
the  first  or  second  minute  of  exercise.  In  addition,  some  records  were 
made  in  the  change  from  walking  to  standing  at  the  end  of  the  experi- 
mental period. 

These  changing  pulse-rates  have  been  termed  the  transition  pulse- 
rates.  To  express  the  rapid  alteration  in  the  heart-action  under 
these  conditions,  we  have  used  the  duration  of  the  pulse-cycle.  While 
the  most  desirable  method  of  recording  these  changes  would  naturally 
be  to  have  the  time-intervals  on  the  photographic  paper  of  such  size 
that  each  pulse-cycle  could  be  readily  measured  in  0.01  second,  the 
labor  and  the  tune  involved  precluded  any  extended  use  of  this  method. 
It  should  be  remembered  that  in  all  this  work  our  interest  was  in  the 
pulse-rate  and,  as  explained  on  page  34,  the  electro-cardiogram  was 
used  simply  as  a  means  of  determining  that  factor  and  not  to  study 
the  type  or  peculiarities  of  the  pulse-cycle.  On  two  occasions  (Feb- 
ruary 28  and  29)  the  paper  was  run  through  the  camera  with  such 
rapidity  that  it  was  possible  to  measure  the  durations  of  the  individual 
cycles.  Ordinarily,  however,  the  rate  of  movement  was  so  adjusted 


298 


METABOLISM   DURING   WALKING. 


that  the  pulse-rate  per  minute  could  be  easily  counted,  but  the  time- 
intervals  on  the  paper  were  too  small  for  the  accurate  measurement 
of  the  duration  of  the  individual  pulse-cycle.  Therefore,  in  order  to 
have  our  period  of  measurement  long  enough  to  secure  reasonably 
accurate  readings  to  0.01  second,  the  cycles  were  measured  in  groups 
of  10.  The  results  given  accordingly  represent  the  average  duration 
of  a  pulse-cycle  as  calculated  from  the  measurement  of  the  time  re- 
quired for  a  group  of  10  pulse-cycles.  The  changes  in  the  average 
duration  as  thus  determined  give  a  clearer  measure  of  altering  heart- 
rate  than  could  be  obtained  by  the  usual  method  of  counting  the  pulse. 
The  changes  in  the  duration  of  the  pulse-cycle  in  the  transition  from 
standing  to  walking  are  shown  in  the  four  curves  in  figure  39.  In  this 
figure  each  point  on  the  abscissa  represents  the  average  of  10  consecu- 
tive pulse-cycles,  while  the  duration  of  the  pulse-cycle  is  given  in  0.01 
second  as  the  ordinate.  The  pulse-rates  equivalent  to  the  measured 
durations  are  shown  on  the  right.  As  the  duration  of  the  cycle  is 
changing,  the  time  required  for  a  group  of  cycles  also  changes,  but  the 
approximate  elapsed  times  are  indicated  for  groups  of  100  cycles  by 
email  figures  and  inclusion  marks  below  the  curves.  The  point  at 
which  the  subject  began  to  walk  is  shown  on  the  curve  by  the  letter  X. 


030t 


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PULSE  CYCLES 


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FIQ.  39. — Duration  of  pulse-cycles  of  E.  D.  B.  in  transition  from  standing  to 
grade  walking,  as  indicated  by  average  cycle  duration  for  measured 
groups  of  10  pulse-cycles. 

Beginning  of  walking  at  X.  A,  Feb.  18;  B,  Feb.  21;  C,  Feb.  19;  D,  Feb.  22. 
The  time  required  for  groups  of  cycles,  varying  in  number,  is  indicated  by 
email  figures  and  inclusion  marks  at  the  bottom  of  the  charts. 

The  cycles  to  the  left  of  X  accordingly  represent  measurements  for  the 
standing  position  and  to  the  right  those  for  grade  walking.  The 
average  grades  and  speeds  used  in  the  walking  are  indicated  for  each 
curve. 

In  figure  39,  a  noticeable  feature  is  the  wide  variation  in  the  duration 
of  the  pulse-cycles  while  the  subject  was  standing,  as  shown  by  the 
variability  of  the  portion  of  each  curve  at  the  left  of  X.  The  measure- 
ments for  the  standing  position  were  made  with  the  same  degree  of 
accuracy  as  those  obtained  during  the  walking,  and  there  is  no  reason 
to  doubt  the  presence  of  these  wide  differences.  Measurements  of 


PHYSIOLOGICAL   CHANGES   IN   TRANSITION.  299 

similar  character,  which  were  made  subsequent  to  this  work  and  re- 
ported by  Benedict,  Miles,  Roth,  and  Smith,1  showed  like  irregularities 
which  were  explained  by  the  investigators  as  due  in  all  probability  to  a 
psychical  stimulus  occasioned  by  the  warning  signal  for  starting. 
Though  no  signal  for  starting  was  given  in  the  experiments  here  rep- 
resented, the  explanation  may  apply  to  these  curves  also,  for  the  sub- 
ject was  naturally  conscious  that  walking  would  begin  at  any  moment, 
as  there  were  certain  routine  movements  which  he  would  recognize  as 
preceding  the  start.  These  irregular  factors  of  duration  have  one 
noticeable  feature  in  common,  namely,  one  or  more  points  of  a  retarded 
pulse,  i.  e.,  of  lengthened  duration.  It  does  not  appear  that  the 
lengthening  was  in  any  way  related  to  the  beginning  of  walking, 
though  one  might  expect  that  it  marked  the  period  when  the  subject 
realized  that  the  operator  was  ready  to  open  the  air-valve  and  start 
the  treadmill. 

It  is  also  apparent  from  these  curves  that  the  average  cycle  duration 
shortened  uniformly  during  walking  to  a  minimum  duration  which  was 
reached  in  from  150  to  200  cycles,  the  greater  portion  of  this  change 
occurring  in  the  first  100  cycles,  with  the  change  gradually  diminishing. 
On  two  days  (see  curves  A  and  B),  a  slight  tendency  to  a  reaction  set 
in  at  approximately  100  cycles.  The  time  when  the  minimum  dura- 
tion was  reached  is  seen  to  be  approximately  1  minute  and,  except  in 
curve  C,  this  minimum  was  held  with  a  considerable  degree  of  con- 
stancy in  the  remainder  of  the  record,  i.  e.,  to  the  end  of  the  second 
minute.  It  is  thus  evident  that  the  pulse-rate  increased  to  meet  the 
demand  of  the  added  work  placed  upon  the  body  within  approximately 
150  cycles  and  with  a  time  lapse  of  between  1  and  2  minutes.  Beyond 
this  point  there  would  undoubtedly  be  some  rise  and  some  variation, 
but  the  greater  part  of  the  pulse  change  occurred  in  the  first  minute 
for  the  conditions  of  work  illustrated  here. 

To  compare  the  pulse-cycles  over  greater  intervals  of  tune,  a  more 
extended  record  of  five  curves  is  given  in  figure  40.  In  these  records 
we  have  attempted  to  measure  the  individual  cycles  and  each  point 
represents  the  average  of  2  cycles  thus  measured.  Since  under  these 
conditions  there  is  more  or  less  error  in  the  estimation  of  fractions  of 
time  intervals,  not  a  little  of  the  irregularity  shown  in  the  pulse-cycles 
for  standing  may  be  due  to  this  cause.  Curve  A  in  figure  40  is  a  record 
taken  during  the  middle  of  a  standing  period  at  9h  44m  a.  m.  on  Feb- 
ruary 28,  1916.  Even  allowing  for  the  errors  of  measurement,  it  is 
evident  that  during  standing  there  were  constant  fluctuations  in  the 
duration  of  the  pulse-cycle  like  those  found  in  the  standing  portions  of 
the  curves  in  figure  39.  Between  the  minimum  and  maximum  dura- 
tions there  was  a  total  difference  of  0.34  second,  this  change  occurring 
within  8  cycles.  The  second  curve  (B),  which  is  not  continuous  with 
curve  A,  includes  the  transition  from  standing  to  walking.  Like  the 
curves  in  figure  39,  the  standing  portion,  which  is  indicated  by  the  re- 
Benedict,  Miles,  Roth,  and  Smith,  Carnegie  Inst.  Waah.  Pub.  No.  280,  1919,  p.  429. 


300 


METABOLISM   DURING   WALKING. 


versed  numbering  of  the  groups  of  cycles,  shows  similar  irregularities 
and  marked  lengthening  in  the  deration  of  the  cycles  previous  to  the 
beginning  of  walking  at  X.  The  rise  in  the  curve  subsequent  to  the 
beginning  of  walking  was  decided  and  regular  for  20  cycles,  or  approxi- 
mately 15  seconds.  Thereafter  the  rise  was  more  gradual,  and  after 
1  minute  of  walking  the  rate  was  fairly  uniform  at  0.45  second.  Curve 
C  is  a  record  taken  after  the  walking  had  been  in  progress  for  2  minutes 
and  covers  a  period  of  approximately  1  %  minutes.  During  most  of  this 
time  the  pulse-cycle  was  between  0.5  and  0.4  second  in  duration, 
shortening  slightly  with  the  time  and  ending  at  0.4  second. 


0.30 


.40 


1.00 


1.10 


1.20 


0       10      20     30      40      20 
PULSE  CYCLES 


10      20     30      40     50      60      70     80      90     100    110    120    130 


FIG.  40. — Duration  of  pulse-cycles  of  E.  D.  B.  in  grade-walking  experiment  of  Feb.  28,  1916, 

as  indicated  by  averages  of  2  pulse-cycles,  measured  individually. 

A,  standing;  B,  transition  standing  to  walking;  beginning  of  walking  at  X;  C,  D,  and  E,  walking 
after  2,  26,  and  30  minutes,  respectively,  of  continuous  walking.  Curves  D  and  E  with 
lengthened  record  of  time-interval.  The  time  required  for  groups  of  cycles,  varying  in 
number,  is  indicated  by  small  figures  and.  inclusion  marks  below  each  curve. 

After  the  subject  had  been  walking  continuously  26  minutes,  a 
record  was  taken  in  which  the  photographic  paper  was  put  through 
the  camera  at  a  rate  of  approximately  5  cm.  a  second,  which  produced 
a  space  interval  between  the  pulse-cycles  of  from  12  to  15  mm.  This 
permitted  measurements  with  a  greater  degree  of  accuracy,  the  results 
being  given  in  curves  D  and  E.  As  in  the  other  curves,  the  points 
represent  the  averages  of  2  cycles.  The  durations  of  the  pulse-cycles 


PHYSIOLOGICAL   CHANGES   IN   TRANSITION. 


301 


shown  in  curve  D  are  practically  constant,  varying  from  0.44  to  0.48 
second  throughout  a  record  of  three-quarters  of  a  minute,  thus  indi- 
cating a  more  uniform  duration  of  the  pulse-cycle  than  that  shown 
by  curve  C.  The  second  record  taken  by  this  method  (curve  E) 
was  made  after  a  total  period  of  walking  of  30  minutes.  During  the 
144  cycles  in  this  curve,  the  length  of  cycle  varied  only  from  0.37  to 
0.39  second.  These  two  records  show  a  remarkably  constant  cycle 
duration  after  a  sufficient  period  of  time  had  elapsed  for  the  body  to 
become  adjusted  to  the  needs  of  the  exercise  of  walking.  While  they 


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.80 
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PULSE  CYCLES 


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10  20   30   40   50   60   70   80   90  100  110 


FIG.  41. — Duration  of  pulse-cycles  of  E.  D.  B.  in  grade-walking  experiment  of  February  29,  1916, 
as  indicated  by  averages  of  two  pulse-cycles  measured  individually. 

A,  standing;  B,  transition  standing  to  walking,  beginning  of  walking  at  X.  C,  walking  26  min- 
utes after  X.  D  and  E,  standing  8  and  14  minutes,  respectively,  after  end  of  walking. 
All  curves  except  B  with  lengthened  record  of  time-interval.  The  time  required  for  groups 
of  cycles,  varying  in  number,  is  indicated  for  curve  B  by  email  figures  and  inclusion  marks 
at  the  bottom  of  the  chart. 

also  indicate  that  the  irregularities  in  the  duration  of  the  pulse-cycle 
in  the  few  seconds  preceding  walking  may  in  part  be  due  to  errors  of 
measurement,  it  is  believed,  for  reasons  given  later,  that  these  irregu- 
larities are  present,  and  that  the  relative  behavior  of  the  pulse  for  stand- 
ing and  walking  as  shown  by  the  curves  in  figure  40  is  correct. 


302  METABOLISM    DURING   WALKING. 

Figure  41  gives  5  curves  of  the  duration  of  the  pulse-cycles  on  Feb- 
ruary 29,  each  point,  as  in  figure  40,  being  the  average  of  2  cycles. 
Curve  A  represents  pulse-cycles  with  the  subject  standing  in  the  second 
period  of  the  day,  and  exhibits  like  variations  to  those  referred  to  in  the 
discussion  of  other  curves.  In  the  corresponding  curve  A  of  figure  40, 
although  the  individual  pulse-cycles  were  measured,  the  time-intervals 
on  the  photographic  paper  were  small,  and  it  was  suggested  that  some  of 
the  irregularities  in  the  curve  may  have  been  due  to  errors  of  measure- 
ment. In  curve  A  of  figure  41,  however,  the  time-interval  was 
lengthened  and  this  source  of  error  was  thus  largely  removed,  but  the 
same  variation  in  the  pulse-cycles  for  standing  is  apparent.  The 
maximum  variations  during  this  record  are  as  large  as  0.4  second,  with 
0.3  second  as  the  greatest  difference  between  two  successive  points. 
In  curve  B,  the  time-interval  was  not  lengthened  and  the  errors  in 
estimating  the  fractions  of  a  second  are  therefore  greater.  The  stand- 
ing portion  of  the  curve,  as  in  the  curves  earlier  discussed,  shows  gross 
variations  in  the  cy  )le  duration.  On  the  transition  to  walking  there  is 
a  lengthening  of  pulse-cycle  duration  which  is  directly  at  variance  with 
the  other  records  given  in  figures  39  and  40.  The  question  may  fairly 
be  raised  if  the  time  of  transition  were  correctly  indicated  on  the 
photographic  paper  and  if  it  may  not  have  been  a  second  or  two  later. 
As  in  the  preceding  figures,  the  major  portion  of  the  rise  in  the  curve 
had  taken  place  by  the  measurement  of  the  fortieth  or  fiftieth  cycle, 
with  an  average  cycle  duration  at  that  tune  of  0.5  second.  Thereafter, 
the  change  in  the  duration  was  but  slight,  reaching  an  approximate 
value  of  0.45  second  at  the  end  of  the  curve,  which  covers  a  time-inter- 
val of  65  seconds. 

After  the  subject  had  been  walking  26  minutes,  a  short  record  was 
made  (curve  C)  in  which  the  tune-intervals  on  the  record  were 
lengthened  by  increasing  the  speed  of  feeding  the  paper  to  the  camera. 
It  may  be  noted  that  in  this  curve  (C),  the  duration  of  the  pulse-cycle 
had  further  shortened  to  0.36  to  0.39  second,  and  there  is  less  variation 
between  the  readings.  This  is  in  harmony  with  curves  D  and  E  of 
figure  40,  which  illustrated  the  regularity  of  the  pulse-cycle  duration 
after  a  continued  period  of  exercise.  Curves  D  and  E  in  figure  41 
will  be  considered  subsequently,  as  they  represent  records  taken  when 
the  man  was  standing  after  walking. 

From  these  measurements  of  the  durations  of  the  pulse-cycle  in  the 
transition  from  standing  to  grade  walking,  there  is  evidence  that  the 
standing  pulse  varied  widely  between  successive  cycles;  that  the  inter- 
val preceding  walking  is  likely  to  be  influenced  by  psychical  effects 
due  to  the  anticipation  of  the  starting  of  the  treadmill;  that  most  of  the 
rapid  shortening  of  the  cycle  duration  after  the  beginning  of  walking 
occurs  within  25  or  30  cycles,  or  about  15  to  20  seconds,  and  is  over 
within  1  minute;  and  that  the  shortening  of  the  duration  thereafter  is 
very  gradual  and  may  continue  for  a  period  of  25  to  30  minutes. 


PHYSIOLOGICAL   CHANGES   IN  TRANSITION.  303 

PULSE-RATE  IN  TRANSITION  FBOM  GRADE  WALKING  TO  STANDING. 

The  changes  in  the  duration  of  the  pulse-cycle  occurring  when  the 
subject  stopped  walking  and  stood  are  shown  in  curves  D  and  E  in 
figure  41  and  also  in  four  curves  in  figure  42.  Curve  D  hi  figure  41 
represents  the  records  obtained  after  the  subject  had  stood  8  minutes. 
Like  curve  C  in  the  same  figure,  this  record  was  made  with  the  time- 
intervals  lengthened  by  an  increase  in  the  speed  of  the  paper  through 
the  camera,  and  is  thus  largely  free  from  errors  of  measurement. 
During  this  record  there  was  difficulty  with  the  feed  of  the  paper 
at  the  points  indicated  by  the  broken  lines,  and  the  record  is  not 
continuous  for  5  to  7  seconds  on  account  of  the  slipping  of  the  feed- 
rolls  and  overexposure  of  the  paper.  Notwithstanding  this,  the  record 
shows  that  the  duration  of  the  cycle  had  lengthened  from  the  walking 
duration  of  0.4  second  to  approximately  0.6  second,  and,  further,  that 
the  variations  of  a  standing  pulse  had  begun  to  appear,  which  have 
already  been  noted  in  previous  discussion  of  figure  40  and  of  curve  A 
in  this  figure. 

Curve  E  is  similar  to  but  not  continuous  with  curve  D,  and  repre- 
sents the  pulse  measured  with  lengthened  time-intervals  after  the 
subject  had  been  standing  for  14  minutes.  A  wide  variation  in  the 
duration  of  cycles  is  seen  in  the  curve,  but  this  variation  differs  from 
that  in  the  other  standing  records,  as  here  a  pronounced  rhythm  is 
present,  occurring  with  each  12  to  14  cycles.  At  first  thought  it 
might  be  said  that  this  rhythm  was  connected  with  the  respiration, 
but  assuming  the  average  pulse-cycle  duration  in  the  curve  is  0.73 
second,  the  time-intervals  for  the  rhythm  would  be  nearly  10  seconds, 
corresponding  to  a  respiration-rate  of  6  respirations  per  minute. 
As  seen  in  table  86  (p.  306),  the  average  respiration-rate  24  minutes 
after  walking  ceased  on  February  29  was  16.9,  and  it  is  unlikely  that 
it  could  have  approached  the  rate  required  by  the  estimated  length  of 
the  rhythm.  The  record  was  made  during  the  middle  of  the  period, 
when  conditions  were  free  from  any  disturbances  which  might  have  a 
tendency  to  stimulate  or  retard  the  pulse-cycle.  The  cause  of  the 
evident  rhythm  remains  unexplained. 

The  changes  in  the  duration  of  the  pulse-cycle  after  walking  ceased 
are  also  shown  in  the  four  curves  in  figure  42.  These  curves  are  con- 
structed in  the  same  way  as  those  in  figure  39,  each  point  indicating 
the  average  duration  of  a  pulse-cycle  as  calculated  from  the  measure- 
ment of  a  group  of  10  cycles,  and  each  square  in  the  figure  representing 
100  cycles.  The  ordinates,  however,  have  been  drawn  to  a  larger  scale 
than  in  figure  39.  The  variations  in  the  pulse-cycles  thus  appear  larger 
than  hi  the  curves  in  figure  39. 

In  curve  A  the  duration  of  the  pulse-cycle  for  the  subject  walking  is 
between  0.33  and  0.34  second.  During  the  first  50  cycles  following 
the  transition,  the  duration  lengthened  to  0.36  second,  with  a  total 


304 


METABOLISM   DURING   WALKING. 


lengthening  of  but  0.02  to  0.03  second.  In  the  next  50  cycles  there 
was  a  further  fall  in.  the  curve  to  0.42  second,  and  by  the  end  of  150 
cycles  the  duration  was  between  0.45  and  0.46  second,  or  a  lengthening 
of  the  cycle  of  but  little  more  than  0.1  second.  This  is  in  decided  con- 
trast to  the  rapid  rate  of  change  shown  in  the  transition  from  standing 
to  walking,  when  most  of  the  change  occurred  within  100  cycles. 
The  150  cycles  of  curve  A  occupied  approximately  1  minute,  and  the 
following  minute  brought  the  duration  to  but  0.49  second.  The  return 
of  the  cycle  duration  during  the  first  few  minutes  of  standing  is  there- 
fore slow  in  comparison  to  the  transition  in  the  change  from  standing  to 
walking. 


0.30 


^K 


% 


D 

186 
176 
167 
158 
100 
143 
36 
30  £ 

25  Sj 

20  £ 

jroa 

\ 

\ 

\ 

\ 

r 

I 

s 

i 

5 

HI 

/ 

i 

2(50    1OO      0      100   200  300  200    100      0       100  200  300    1OO     0      1OO   20O  30O 
PULSE  CYCLES 

FIG.  42. — Duration  of  pulse-cycles  of  E.  D.  B.  in  transition  from  grade  walking  to  stand- 
ing, as  indicated  by  average  cycle  duration  for  measured  groups  of  10  pulse-cycles. 

Beginning  of  standing  at  Y.  A,  Feb.  12;  B,  Feb.  14;  C,  Feb.  17;  D,  Feb.  15.  The  time 
required  for  groups  of  cycles,  varying  in  number,  is  indicated  by  small  figures  and 
inclusion  marks  at  the  bottom  of  each  chart. 

The  behavior  of  the  pulse-cycle  in  curve  B  is  almost  the  same  as  that 
found  in  curve  A.  The  duration  just  previous  to  the  transition  is 
practically  the  same.  At  the  end  of  100  cycles  the  duration  has 
lengthened  to  0.42  second,  or  but  0.08  second.  At  150  cycles,  occupy- 
ing approximately  60  seconds,  the  duration  was  about  0.46  second. 
Two  minutes  of  standing  resulted  in  a  total  lowering  of  the  duration  of 
the  pulse-cycle  0.12  second.  This  curve  shows  some  lag  at  the  transi- 
tion which  other  curves  do  not  show. 

In  curve  C  the  duration  of  the  pulse-cycle  lengthened  from  0.33 
second  preceding  the  transition  to  standing  to  0.37  second  in  50  cycles, 
while  in  150  cycles  after  the  walking  ended,  occupying  approximately 
60  seconds,  the  duration  lengthened  to  0.44  second,  or  a  total  lengthen- 
ing of  0.11  second.  This  rate  of  lengthening  agrees  with  that  found 
in  the  two  preceding  curves,  namely,  in  150  cycles  of  approximately 
60  seconds  of  elapsed  tune,  the  change  in  the  average  duration  of  the 
cycle  was  but  little  over  0.1  second,  and  by  the  end  of  2  minutes  the 


AFTER-EFFECTS   OF   GRADE   WALKING.  305 

lengthening  of  the  duration  of  the  cycle  did  not  reach  0.2  second.  The 
duration  of  the  pulse-cycle  at  the  end  of  2  minutes  is  thus  less  than 
0.5  second,  or,  in  terms  of  pulse-rate  per  minute,  the  change  has  been 
from  176  to  125  beats. 

Curve  D  is  composed  of  5  records,  covering  a  duration  of  147  seconds, 
and  therefore  is  not  continuous.  Consequently,  it  must  be  considered 
on  a  time  basis  rather  than  according  to  the  number  of  consecutive 
pulse-cycles.  For  the  first  70  cycles  the  record  was  continuous  and  the 
elapsed  time  was  30  seconds.  In  this  time  the  duration  lengthened  to 
about  0.41  second,  or  a  total  lengthening  of  0.06  second.  At  the  end 
of  1  minute  the  duration  fell  another  0.01  second,  and  at  the  end  of  the 
record,  after  2  minutes  and  27  seconds  of  standing,  the  duration  of  the 
pulse-cycle  was  0.49  second,  or  0.14  second  longer  than  at  the  transi- 
tion. At  the  end  of  1  minute  or  thereabouts,  all  four  of  these  curves 
begin  to  exhibit  a  marked  irregularity  in  the  duration  of  the  pulse- 
cycles,  similar  to  that  seen  for  the  pulse  during  standing  in  figures 
39,  40,  and  41,  with  some  suggestion  of  a  rhythm  in  curves  A  and  C, 
recalling  that  seen  in  curve  E  in  figure  41. 

From  these  curves  it  appears  that  the  response  to  the  change  from 
walking  to  standing  is  rapid,  although  slightly  slower  than  with  the 
change  from  standing  to  walking;  also,  that  the  lengthening  of  the 
pulse-cycle  after  walking  had  ceased  continues  at  a  uniform  rate  for 
approximately  a  minute,  during  which  time  the  rate  decreases  from 
40  to  50  beats  a  minute.  After  the  immediate  drop  in  the  first  minute, 
the  change  apparently  becomes  less  marked,  with  wide  fluctuations 
in  the  cycle  durations. 

AFTER-EFFECTS  OF  GRADE  WALKING. 

As  a  part  of  the  routine  of  the  research,  a  few  standing  experiments 
were  made  with  E.  D.  B.  following  periods  of  grade  walking,  for  a  study 
of  the  after-effects  of  the  exercise  on  the  standing  metabolism.  The 
results  are  compared  in  table  86,  in  which  the  average  pre- walking 
values  for  the  day  are  taken  from  table  6  and  the  grade-walking  values 
are  drawn  from  table  16.  In  each  case  the  length  of  the  period  of 
walking,  with  the  grade  and  the  speed,  also  the  length  of  period  of  rest 
(sitting)  between  the  walking  and  standing  observations,  are  given  in 
table  86.  As  the  values  for  December  21,  1915,  to  February  17,  1916, 
inclusive,  were  obtained  immediately  after  walking  ceased,  they 
naturally  represent  rapidly  changing  values,  especially  hi  the  earlier 
part  of  the  period. 

The  experiments  of  February  26  to  29,  inclusive,  have  three  post- 
walking  periods  each,  with  an  interval  of  rest,  i.  e.,  sitting,  of  approxi- 
mately 20  to  24  minutes  before  the  measurements  in  the  first  standing 
period  began .  The  last  period  on  each  of  these  days  was  approximately 
2  hours  after  walking.  The  changes  in  these  last  periods  would 


306 


METABOLISM   DURING   WALKING. 


TABLE  86. — Metabolism  of  E.  D.  B.  when  standing  after  grade  walking  in  experiments  without  food. 

(Values  per  minute.) 


Date  and  experimental  conditions.1 

Aver- 
age 
respira- 
tion- 
rate. 

Aver- 
age 
pul- 
monary 
venti- 
lation 
(re- 
duced). 

Aver- 
age 
pulse- 
rate. 

Aver- 
age 
body- 
tem- 
pera- 
ture. 

Carbon 
dioxide. 

Oxy- 
gen. 

Respi- 
ratory 
quo- 
tient. 

Heat 
(com- 
puted). 

Dec.  21,  1915: 
Standing  before  walking  

14  8 

liters. 
8  9 

58 

°C. 

c.  c. 
190 

c.  c. 
207 

0  92 

cals. 
1  02 

Walking  l^O™  ;  20  p.  ct.,  70  m.  p.  m.  .  . 

26.0 

37.0 

1,596 

1,784 

.90 

8  78 

Standing,  no  rest  »  

18.3 

105 

322 

380 

.85 

1  85 

Dec.  22,  1915: 
Standing  before  walking  

12.8 

8  0 

190 

218 

87 

1  07 

Walking  Ih34m;  20  p.  ct.,  70  m.  p.  m.  .  . 

25.7 

34  2 

1,554 

1,748 

.89 

8  59 

Standing,  no  rest  

19  5 

13  6 

102 

307 

367 

84 

1  78 

Dec.  31,  1915: 
Standing  before  walking  

15  2 

9  7 

75 

211 

257 

82 

1  24 

Walking  Ih2ra;  20  p.  ct.,  80  m.  p.  m.  .  . 

27.6 

43.9 

2,042 

2,270 

.90 

1.18 

Standing,  no  rest  

22.2 

16  2 

128 

405 

490 

.83 

2  37 

Jan.  3,  1916: 
Standing  before  walking  

15.6 

9  5 

210 

250 

.84 

1  21 

Walking  Ih39m;  25  p.  ct.,  43  m.  p.  m.  .  . 

23  8 

29  1 

1,183 

1,451 

.82 

7  00 

Standing,  no  rest  

19  2 

12  5 

284 

352 

81 

1  69 

Feb.  12,  1916: 
Standing  before  walking  

14.4 

8  8 

65 

36.80 

191 

244 

.78 

1.17 

Walking  lh;  30  p.  ct.,  72  m.  p.  m  
Standing,  no  rest  

28.4 
21.6 

59.6 

18  4 

163 
122 

37.75 

2,471 
455 

2,613 

528 

.95 
.86 

13.03 
2  57 

Feb.  14,  1916: 
Standing  before  walking  

14  9 

9  2 

77 

37.10 

196 

240 

82 

1   16 

Walking  lh;  30  p.  ct.,  68  m.  p.  m  
Standing,  no  rest  

27.8 
22.1 

54  5 
17  8 

166 
123 

37.98 
38.50 

2,311 
417 

2,481 
511 

.93 

.82 

12.31 
2.47 

Feb.  15,  1916: 
Standing  before  walking  

16.2 

10  1 

79 

36.94 

207 

261 

.79 

1.25 

Walking  Ih21m;35p.  ct.,  45m.  p.  m..  . 
Standing,  no  rest  

27.7 
21   1 

40.5 
14  9 

145 
125 

38.29 
38.53 

1,732 
369 

2,007 
452 

.86 

.82 

9.78 
2  18 

Feb.    16,    1916: 
Standing  before  walking  

15.5 

9.4 

36.88 

205 

255 

.80 

1.22 

Walking  19™  ;  35  p.  ct.  ,  58  m.  p.  m  
Standing,  no  rest  

29.6 
20.9 

54.5 
15  8 

174 
131 

38.27 

2,267 
382 

2,495 
476 

.91 
.80 

12.32 
2.29 

Feb.  17,  1916: 
Standing  before  walking  

16  5 

10  0 

85 

37.13 

210 

267 

.79 

1.28 

Walking  57"  ;  35  p.  ct.  ,  62  m.  p.  m  
Standing,  no  rest  

29.1 
21.3 

61.8 
16.7 

177 
122 

38.08 
38.51 

2,507 
424 

2,725 
520 

.92 

.82 

13.48 
2.51 

Feb.  26,  1916: 
Standing  before  walking  

16.1 

9.4 

70 

37.01 

212 

251 

.84 

1.22 

Walking  Ih4m;  30  p.  ct.,  69  m.  p.  m  
Standing  after  24m  rest  

30.2 
16  7 

54.6 
9.7 

153 
96 

37.61 
38.13 

2,387 
210 

2,592 
273 

.92 

.77 

12.83 
1.30 

Standing,  Ih18m  after  walking2.    .  .  . 

16  7 

9  5 

81 

37.22 

206 

245 

.84 

1.19 

Standing,  2h8m  after  walking2  

16.1 

9.1 

73 

36.71 

210 

267 

.79 

1.28 

Feb.  28,  1916: 
Standing  before  walking  

15.1 

9.1 

69 

36.74 

213 

244 

.87 

1.19 

Walking  Ih2m  ;  30  p.  ct.,  67  m.  p.  m  
Standing  after  20"1  rest  

30.2 
15.4 

55.0 
10.0 

150 
101 

37.11 
38.09 

2,374 
239 

2,508 

282 

.95 

.85 

12.50 
1.37 

Standing,  Ih15m  after  walking2  

15.6 

9.6 

83 

37.30 

223 

252 

.88 

1.23 

Standing,  Ih55m  after  walking2  

16.6 

9.9 

80 

37.19 

218 

266 

.82 

1.28 

Feb.  29,  1916: 
Standing  before  walking  

14.8 

8.8 

68 

36.70 

183 

230 

.80 

1.10 

Walking  34m;  30  p.  ct.,  69  m.  p.  m.  .  . 
Standing  after  24m  rest  

32.1 
16  9 

56.5 
10  3 

153 

37.44 
38.04 

2,284 
213 

2,491 
291 

.92 

.73 

12.33 
1.37 

Standing,  lhlm  after  walking2  

15.9 

9.4 

88 

37.18 

198 

276 

.72 

1.30 

Standing,  Ih50m  after  walking2  

16.3 

9.5 

82 

36.83 

191 

245 

.78 

1.17 

1The  values  for  standing  before  walking  and  for  grade  walking  are  average  values  for  the  day. 
and  16,  pp.  46  and  78.     Those  for  standing  after  walking  are  period  values. 
2During  this  interval  between  the  walking  and  standing,  the  subject  sat  for  a  part  of  the  time. 


AFTER-EFFECTS   OF   GRADE   WALKING.  307 

naturally  be  less,  and  it  might  be  expected  that  values  of  approximately 
the  pre-walking  rate  would  be  found.  In  experimental  periods  con- 
tinuing as  long  as  those  employed  by  us  in  this  study  it  was  naturally 
not  expected  that  the  measurements  would  show  the  gradations  that 
could  be  obtained  by  other  methods;  nevertheless  a  general  comparison 
may  be  made  of  the  metabolism  preceding  and  following  walking. 

In  the  experiments  of  December  21  to  February  17,  inclusive,  it  is 
seen  that  the  data  for  the  respiration,  ventilation,  and  pulse  show  no 
close  approach  to  the  pre-walking  values  since  they  were  obtained 
immediately  on  the  cessation  of  walking.  It  may  be  noted,  however, 
that  although  the  percentages  vary,  the  ventilation-rate  remained 
at  a  higher  level,  relatively,  than  the  respiration-rate,  the  former 
averaging  approximately  70  per  cent  above  the  pre-walking  average 
and  the  respiration-rate  approximately  40  per  cent. 

In  the  first  of  the  post-walking  periods  of  February  26  to  29,  fol- 
lowing 20  or  more  minutes  of  rest,  both  respiration  and  ventilation, 
though  much  reduced,  were  still  above  the  pre-walking  values.  In 
the  third  standing  period,  which  was  approximately  2  hours  after 
walking  had  ceased,  the  data  for  February  26  show  that  the  respira- 
tion-rate and  pulmonary  ventilation  had  fallen  to  the  pre-walking  rate 
during  the  interval,  but  that  on  February  28  and  29  these  factors  were 
still  above  the  pre-walking  averages.  The  pulse  remained  above  the 
pre-walking  rate  on  all  of  these  days.  This  is  in  keeping  with  the  re- 
sults reported  by  Benedict  and  Cathcart,1  who  found  that  the  pulse- 
rates  did  not  readily  return  to  the  pre-walking  level  after  such  pro- 
longed exercise. 

Only  a  few  measurements  of  the  body-temperature  are  available  for 
comparison,  but  these  are  included  in  table  86.  The  post-walking 
temperatures  appear  here  to  be  higher  than  those  obtained  in  the 
walking  periods.  This  is  contrary  to  the  curves  in  figures  33  to  37. 
inclusive,  which  show  a  rapid  fall  in  body-temperature  after  walking 
ceased.  This  difference  in  direction  is  due  to  the  fact  that  the  temper- 
ature values  for  walking  given  in  table  86  represent  averages  of  all  the 
walking  periods  of  the  day,  and  thus  no  sharp  comparison  of  the  walk- 
ing and  standing  values  is  possible  here.  The  special  interest  in  this 
connection  is,  however,  the  comparison  between  the  temperatures 
with  the  subject  standing  before  and  after  walking.  It  is  seen  that 
for  the  periods  of  standing  immediately  after  walking,  the  average 
body-temperature  is  1.5°  C.  higher  than  the  pre-walking  tempera- 
ture and  for  the  first  post-walking  periods  on  the  days  when  a  rest 
interval  of  but  24  minutes  intervened  the  difference  is  but  little  less. 
By  the  second  post-walking  period,  the  temperatures  are  still  nearly 
0.5°  C.  above  the  pre-walking  temperature.  It  is  not  until  the  third 

Benedict  and  Cathcart,  Carnegie  Inst.  Wash.  Pub.  No.  187,  1913,  p.  153. 


308  METABOLISM   DURING   WALKING. 

period,  representing  a  time-interval  of  2  hours  after  walking  ceased, 
that  the  temperature  may  be  said  to  approximate  anything  like  the 
original  values. 

The  after-effects  of  exercise  on  the  gaseous  exchange  have  recently 
been  studied  by  Campbell,  Douglas,  and  Hobson,1  and  by  Krogh  and 
Lindhard,2  who  followed  the  changes  through  brief  intervals.  These 
authors  find,  in  harmony  with  Zuntz,  with  Benedict  and  Cathcart,  and 
with  others,  that  the  respiratory  quotient  increases  when  the  work 
stops;  after  a  brief  period  it  falls  to  a  value  somewhat  below  normal. 

The  values  here  reported  for  15-minute  periods  do  not,  of  course, 
show  the  stimulated  respiratory  quotient  for  the  post-walking  periods 
which,  according  to  Krogh  and  Lindhard,  occurs  approximately 
1|  minutes  after  the  end  of  walking.  In  the  standing  periods  follow- 
ing immediately  after  the  cessation  of  walking  (December  21  to 
February  17),  the  respiratory  quotient  is  lower  than  during  the  walking 
period,  and  but  little  different  from  the  pre-walking  quotients.  This 
is  probably  explained  by  the  fact  that  the  quotients  for  a  period  fol- 
lowing immediately  the  cessation  of  walking  would  be  influenced  by 
the  high  values  referred  to  above  as  occurring  for  a  short  time.  It  is 
only  when  the  periods  are  taken  after  the  temporary  high  respiratory 
quotients  have  passed  that  the  after-effects  of  walking  become  evident. 
All  of  the  post- walking  periods  of  February  26  to  29  on  which  there 
was  an  interval  of  rest  following  the  walking  indicate  a  lowered  respi- 
ratory quotient  in  relation  to  both  the  pre-walking  and  the  walking 
respiratory  quotients.  On  two  of  these  days  the  subject  had  walked 
somewhat  over  an  hour  and  on  the  last  day  about  half  that  tune. 

Campbell,  Douglas,  and  Hobson  conclude  that  the  possible  presence 
of  lactic  acid  in  the  muscles  is  alone  not  sufficient  to  explain  the  be- 
havior of  the  respiratory  quotient  following  the  cessation  of  work  and 
are  inclined  to  believe  with  Zuntz  and  with  Benedict  and  Cathcart 
that  the  probable  explanation  is  that  during  the  period  of  walking  the 
glycogen  reserve  in  the  body  is  depleted  and  that  during  the  subse- 
quent periods  proportionally  less  carbohydrate  than  fat  is  consumed 
in  the  body  metabolism. 

A  rough  estimate  of  the  amounts  of  glycogen  consumed  during  1 
hour  of  walking  on  the  basis  of  an  oxygen  consumption  of  2,500  c.  c. 
per  minute  and  a  respiratory  quotient  of  0.90  is  as  follows:  The  total 
energy  produced  in  1  hour  would  be  approximately  750  calories;  if 
60  per  cent  of  this  energy  were  derived  from  carbohydrate  to  produce 
the  respiratory  quotient  of  0.90,  as  assumed  by  Magnus-Levy,3  and 
4.23  calories  be  assumed  as  the  heat-production  from  1  gram  of  gly- 
cogen, the  total  amount  of  glycogen  consumed  in  1  hour  of  walking 

'Campbell,  Douglas,  and  Hobson,  Phil.  Trans.,  London,  1920,  Ser.  B,  210,  p.  1. 
2Krogh  and  Lindhard,  Journ.  Physiol.,  1920,  53,  p.  431. 

3Magnus-Levy,  in  von  Noorden's  Handbuch  der  Pathologie  des  Stoffwechsels,  Berlin,  2d  ed., 
1906,  1,  p.  207. 


SUMMARY   OP   RESULTS.  309 

would  be  somewhat  over  100  grams,  i.  e.,  more  than  one-fourth  of  the 
amount  believed  to  be  present  normally  in  the  body.  Benedict  and 
Cathcart1  report  low  respiratory  quotients  5  hours  after  exercise,  and 
Zuntz  and  Schumburg2  maintain  that  the  carbohydrate  reserve  was 
not  established  with  their  subject  until  the  following  day. 

The  stimulating  effect  of  walking  is  also  seen  from  the  experiments 
of  February  26  to  29,  in  that  the  gaseous  metabolism  remained  above 
the  pre-walking  values  even  after  a  lapse  of  2  houis  following  the  cessa- 
tion of  walking.  Only  on  February  26  did  the  metabolism  reach  the 
pre-walking  values  in  the  case  of  the  carbon  dioxide,  for  on  both  of  the 
other  days  the  carbon  dioxide  was  still  slightly  above  standing  normal 
requirements  at  the  end  of  the  observations.  The  oxygen  consumption, 
which  is  the  best  index  of  the  metabolism,  was  above  the  pre-walking 
requirements  by  approximately  7  per  cent  after  the  lapse  of  2  hours. 

SUMMARY  OF  RESULTS. 

In  the  preceding  pages  it  has  been  found  that  the  average  standing 
metabolism  obtained  with  the  subjects  studied  was  1.18  calories  per 
kilogram  of  body-weight  per  hour,  or  28.4  calories  per  24  hours.  (See 
table  19.)  This,  when  compared  with  average  metabolism  for  the  lying 
position  of  25.3  calories  per  kilogram  of  body- weight  per  24  hours  (see 
table  17),  represents  an  increase  for  the  standing  position  of  12  per  cent. 

When  the  standing  requirements  are  used  as  a  basis,  it  is  found  that 
the  increase  in  the  energy  expended  in  horizontal  walking  over  the 
energy  output  for  the  standing  position  varied  for  the  8  subjects  from 
0.454  to  0.618  gram-calorie  for  each  horizontal  kilogrammeter,  i.  e., 
the  transportation  of  1  kilogram  a  distance  of  1  meter  hi  a  hori- 
zontal direction.  For  the  two  subjects  W.  K.  and  E.  D.  B.,  with 
whom  most  of  the  work  in  this  research  was  done,  the  increase  for  the 
horizontal  walking  in  the  energy  expended  was  0.490  and  0.478  gram- 
calorie,  respectively,  for  each  horizontal  kilogrammeter.  These  values 
are  below  the  average  value  used  by  other  investigators,  but  show 
good  agreement.  The  total  energy  expended  per  meter  increase  in 
speed  was  not  measurably  affected  until  a  speed  of  80  meters  a  min- 
ute was  reached,  beyond  which  point  each  meter  increase  in  speed 
required  a  proportionately  greater  increase  in  the  energy  consump- 
tion. (See  table  37.) 

In  grade  walking  the  total  heat  expended  increased  uniformly  per 
kilogrammeter  of  work  performed  at  each  grade,  but  was  somewhat  less 
when  the  same  amount  of  work  was  derived  from  a  high  grade  and  a 
low  speed  than  when  due  to  a  low  grade  and  high  speed.  (See  figs.  21 
and  22.)  The  total  outlay  was  from  15  to  12  gram-calories  per  kilo- 
grammeter for  amounts  of  work  ranging  from  300  to  600  kg.  m.  per 

Benedict  and  Cathcart,  Carnegie  Inst.  Wash.  Pub.  No.  187,  1913,  p.  172. 
2Zuntz  and  Schumburg,  Physiologic  des  Marsches,  Berlin,  1901,  p.  255. 


310  METABOLISM   DURING   WALKING. 

minute,  and  from  12  to  10  gram-calories  per  kilogrammeter  when  the 
work  was  between  1,000  and  1,500  kg.  m.  per  minute.  (See  also 
table  62.) 

The  average  increment  in  the  heat-output  due  to  grade  walking 
was  approximately  7.5  gram-calories  per  kilogrammeter  of  work  per- 
formed. From  the  results  of  this  study  it  may  be  said  that  the  net 
efficiency  with  which  a  person  can  walk  up-grade  is  not  far  from  30  per 
cent  when  the  work  is  under  500  kg.  m.  per  minute,  but  when  the  work 
amounts  to  more  than  500  kg.  m.  per  minute,  the  efficiency  decreases 
as  the  work  increases.  (See  table  69.) 

The  measurements  of  the  pulmonary  ventilation  during  grade  walk- 
ing show  that  the  increase  in  this  physiological  factor  for  each  increase 
of  100  kg.  m.  of  work  was  from  3  to  5  liters,  while  the  total  percentage 
increase  with  excessive  work  was  as  much  as  850  per  cent  above  the 
standing  requirement.  (See  tables  76  and  77.)  This  enormous  in- 
crease indicates  the  wide  margin  which  must  be  provided  in  designing 
gas-masks  to  be  worn  during  excessive  muscular  work. 

During  grade  walking,  the  respiration-rate  for  the  subject  E.  D.  B. 
showed  constant  increase  over  the  standing  value  of  1.2  respirations 
for  each  100  kg.  m.  increase  in  the  work  when  over  500  kg.  m.  of  work 
was  done.  With  the  subject  W.  K.  the  increase  over  the  standing  res- 
piration-rate was  more  nearly  2  respirations  per  100  kg.  m.  (See  tables 
74  and  75.)  The  percentage  increase  over  the  standing  rate  was  from 
8  to  10  per  cent  for  W.  K.,  while  for  E.  D.  B.  the  increase  was  as  high 
as  40  per  cent  for  the  first  100  kg.  m.,  but  fell  rapidly  with  increase  in 
the  amount  of  work  and  became  constant  at  approximately  8  per  cent. 

In  horizontal  walking  the  pulse-rate  frequently  was  less  than  that 
with  the  subject  standing,  even  with  an  increase  in  the  metabolism  of 
100  to  200  per  cent.  During  grade  walking,  the  pulse-rate  showed  a 
practically  uniform  increase  with  the  increase  in  the  amount  of  work 
performed.  The  increment  in  the  pulse-rate  over  the  rate  found  for  the 
standing  position  rose  rapidly  with  the  increase  in  the  work  performed ; 
though  the  percentage  increase  per  100  kg.  m.  of  work  remained  fairly 
constant,  considerable  differences  were  shown  between  individuals. 
(See  tables  78  and  79.) 

The  body- temperature  showed  increases  as  high  as  2°  C.,  indicat- 
ing for  a  body-weight  of  60  kilograms  a  storage  of  heat  in  the  body 
of  approximately  100  calories. 

From  the  measurements  taken  at  the  time  of  transition  from  stand- 
ing to  grade  walking,  it  is  believed  that  in  most  cases  the  body  adjusts 
itself  to  the  new  demands  as  to  pulse,  respiration -rate,  pulmonary 
ventilation,  and  oxygen-supply  by  the  end  of  the  third  minute,  and 
by  far  the  larger  part  of  the  adjustment  has  occurred  within  30  sec- 
onds. The  recovery  after  exercise,  however,  is  not  so  prompt,  and 
the  after-effects  of  the  walking  persist  for  a  much  longer  time  before 
initial  conditions  are  reestablished. 


7770 


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